Genome-wide analysis of fatty acid desaturase genes in chia (Salvia hispanica) reveals their crucial roles in cold response and seed oil formation.

Chia (Salvia hispanica) is a functional food crop with high α-linolenic acid (ALA), the omega-3 essential fatty acid, but its worldwide plantation is limited by cold-intolerance and strict short-photoperiod flowering feature. Fatty acid desaturases (FADs) are responsible for seed oil accumulation, and play important roles in cold stress tolerance of plants. To date, there is no report on systemically genome-wide analysis of FAD genes in chia (ShiFADs). In this study, 31 ShiFAD genes were identified, 3 of which contained 2 alternative splicing transcripts, and they were located in 6 chromosomes of chia. Phylogenetic analysis classified the ShiFAD proteins into 7 groups, with conserved gene structure and MEME motifs within each group. Tandem and segmental duplications coursed the expansion of ShiFAD genes. Numerous cis-regulatory elements, including hormone response elements, growth and development elements, biotic/abiotic stress response elements, and transcription factor binding sites, were predicted in ShiFAD promoters. 24 miRNAs targeting ShiFAD genes were identified at whole-genome level. In total, 15 SSR loci were predicted in ShiFAD genes/promoters. RNA-seq data showed that ShiFAD genes were expressed in various organs with different levels. qRT-PCR detection revealed the inducibility of ShiSAD2 and ShiSAD7 in response to cold stress, and validated the seed-specific expression of ShiSAD11a. Yeast expression of ShiSAD11a confirmed the catalytic activity of its encoded protein, and its heterologous expression in Arabidopsis thaliana significantly increased seed oleic acid content. This work lays a foundation for molecular dissection of chia high-ALA trait and functional study of ShiFAD genes in cold tolerance.

Effects of standardized ileal digestible lysine on growth performance and economic return in duroc-sired finishing pigs.

In the United States, emphasis has shifted toward improved pork quality and has resulted in greater use of Duroc-based terminal sires. Duroc sires have differences in ADG, ADFI, G:F, and carcass leanness compared to other sires. Therefore, our objective was to determine the standardized ileal digestible (SID) Lys estimates for Duroc-based sired finishing pigs. In Exp. 1, 2,124 pigs (DNA 600 ×PIC 1050, initially 48.9 kg) were used with 24-27 pigs per pen and 16 pens per treatment. Corn-soybean meal-based diets were fed in three phases (49-59, 59-71, and 71-81 kg). Pens were randomly allotted to 1 of 5 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 95%, 103%, 110%, and 120%). Phase 1 diets were formulated to 0.90%, 1.01%, 1.09%, 1.17%, and 1.27%, phase 2 to 0.79%, 0.87%, 0.94%, 1.03%, and 1.10%, and phase 3 to 0.71%, 0.78%, 0.85%, 0.92%, and 0.99% SID Lys. Increasing SID Lys increased (linear, P < 0.001) ADG and Lys intake/kg of gain. A marginally significant improvement (quadratic, P = 0.071) in G:F was observed as SID Lys increased. Feed cost, feed cost/kg of gain, revenue (linear, P < 0.01) and income over feed cost (IOFC) increased (quadratic, P = 0.045) with increasing SID Lys. In Exp. 2, 2,099 pigs (DNA 600 ×PIC 1050, initially 90.1 kg) were used with 24-27 pigs per pen and 20 pens per treatment. Corn-soybean meal-based diets were fed in 2 phases (90-106 and 106-136 kg). Pens were randomly allotted to 1 of 4 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 93%, 100%, and 110%). Phase 1 diets were formulated to 0.65%, 0.71%, 0.77%, and 0.84% and phase 2 to 0.60%, 0.66%, 0.71%, and 0.78% SID Lys. Overall, increasing SID Lys increased (linear, P < 0.05) G:F, Lys intake/kg of gain, live weight and HCW, and increased (quadratic, P = 0.020) ADG. Feed cost (linear, P < 0.01), revenue, and IOFC increased (quadratic, P ≤ 0.053) with increasing SID Lys. In conclusion, the SID Lys estimate for growth and IOFC was 1.19% or 4.63 g SID Lys/Mcal of NE, 1.05% or 4.04 g SID Lys/Mcal of NE, and 0.94% or 3.58 g SID Lys/Mcal of NE for pigs weighing 49-59 kg, 59-71 kg, and 71-81 kg, respectively. The SID Lys estimate for late finishing pigs was 0.74%-0.81% or 2.85-3.10 g SID Lys/Mcal of NE, and 0.69%-0.75% or 2.61-2.84 g SID Lys/Mcal of NE, for 90-106 kg and 106-136 kg pigs, respectively. These data provide SID Lys estimates for current Duroc-sired genetic lines raised in a commercial environment.

Interventions to reduce porcine epidemic diarrhea virus prevalence in feed in a Chinese swine production system: A case study.

Research has shown that feed and feed ingredients can be one of the potential routes of transmitting viral pathogens into swine farms. In this short communication, we report two cases of Porcine Epidemic Diarrhea (PED) in two sow farms located in eastern China. Immediately after the outbreaks, extensive sampling and testing for genetic materials of PEDV was carried out on farms, and at the feed mill, in an effort to identify possible sources of infection based on field observations of local area viral spread and interventions already implemented to lower risk of this spread. Samples collected from personnel or supplies entering the farms were inspected and proved as low risk factors. In contrast, feed and feed ingredient samples collected at the on-farm feed bins, and at the feed mill, tested positive for PEDV RNA. Based on these data, multiple interventions to lower viral spread via feed were implemented including (1) simplification of diet formulation excluding high-risk ingredients, (2) extension of thermal treatment during pellet conditioning and (3) maximising feed quarantine on farm up to 7 days from feed delivery to consumption. Collectively, these interventions appeared to have a positive effect as the prevalence of PED-related disease and the number of PEDV-positive feed or feed ingredient samples decreased considerably following implementation.

Evaluation of Enogen Feed Corn on growth performance and carcass characteristics of finishing pigs.

Enogen Feed Corn (EFC; Syngenta Seeds, LLC, Downers Grove, IL) hybrids contain a trait for expression of heat-stable α-amylase in the grain. α-Amylase is an enzyme responsible for breakdown of starch in the small intestine; supplementation of exogenous α-amylase to pigs may result in greater starch digestibility and thus improved gain efficiency. A total of 288 pigs (Line 600 × 241, DNA, Columbus, NE; initially 41.6 kg) were utilized in an 82-d trial to determine if replacing conventional yellow dent corn (CONV) with EFC in diets with or without distillers dried grains with solubles (DDGS) influences growth performance and carcass characteristics. Pens of pigs were randomly assigned to one of four dietary treatments balancing for initial body weight. There were nine pens per treatment with eight pigs per pen (an equal number of barrows and gilts per pen). Treatments were arranged in a 2 × 2 factorial with main effects of corn source (CONV or EFC) and DDGS (0% or 25%). Experimental diets were fed in meal form in three phases: days 0 to 29, 29 to 47, and 47 to 82. Pigs were weighed approximately every 2 wk and at the beginning of each phase. On day 82, pigs were transported to a commercial abattoir for processing and carcass data collection. Data were analyzed using PROC GLIMMIX procedure of SAS with pen as the experimental unit. There were no corn source by DDGS interactions (P > 0.05) observed for overall performance or carcass characteristics. Overall, average daily gain (ADG) was marginally greater (P < 0.089) for pigs fed EFC than CONV with no evidence (P > 0.196) for difference in average daily feed intake (ADFI), gain:feed ratio (G:F), hot carcass weight (HCW), or other carcass traits. Addition of DDGS decreased (P < 0.047) overall ADG and G:F. Pigs fed DDGS had marginally lower (P < 0.071) HCW, less (P < 0.050) backfat depth, greater (P < 0.026) loin depth, and greater (P < 0.020) percentage lean and carcass fat iodine value (IV). In summary, addition of 25% DDGS to the diet decreased ADG and increased carcass fat IV. Pigs fed EFC tended to have improved overall ADG; however, G:F and carcass characteristics were not different between corn sources. These results suggest that EFC, although not beneficial, may be used as a substitute for CONV without any deleterious effects on growth performance. Further research should be conducted to understand whether addition of EFC to swine diets could be beneficial in younger pigs exhibiting decreased pancreatic α-amylase secretion following weaning or whether heat treatment of diets, such as pelleting, may influence the response to EFC.

The effects of dietary soybean hulls particle size and diet form on nursery and finishing pig performance.

Two experiments were conducted to investigate increasing unground and finely ground soybean hulls fed in meal or pelleted form on nursery and finishing pig performance. In experiment 1, 1,100 nursery pigs (initially 6.8 ± 0.1 kg and 28 d of age) were used in a 42-d study with 11 replicates per treatment. Treatments were arranged in a 2 × 2 × 2 factorial with main effects of soybean hulls (10% vs. 20%), grind type (unground, 617 µ vs. ground, 398 µ), and diet type (pelleted vs. meal form). No three-way or soybean hull level × grind type interactions were observed. Overall, average daily gain (ADG) was increased (P < 0.05) by pelleting, decreased (P < 0.05) by grinding, but unaffected by soybean hull levels. Grind type × diet form interactions were observed (P < 0.05) for gain:feed ratio (G:F) and a tendency for average daily feed intake (ADFI; P < 0.10). This was because grinding soybean hulls decreased (P < 0.05) ADFI and increased (P < 0.05) G:F when fed in meal form; however, grinding did not affect ADFI and decreased (P < 0.05) G:F when diets were pelleted. Increasing soybean hulls increased (P < 0.05) ADFI and decreased (P < 0.05) G:F when diets were fed in meal form, but these effects were not observed when diets were pelleted (diet form × soybean hull level interaction, P < 0.06). In experiment 2, 1,215 pigs (initially 21.1 ± 0.1 kg) were used in a 118-d study with nine replications per treatment. Treatments were a corn-soybean meal-based control diet and four diets arranged in a 2 × 2 factorial with the main effects of soybean hulls (7.5% vs. 15%) and grind type (unground, 787 µ vs. ground, 370 µ). All diets were fed in meal form. No soybean hull level × grind type interactions were observed for any growth or carcass responses. Increasing dietary soybean hulls from 0% to 15%, regardless of particle size, did not affect ADG or ADFI, but decreased (linear, P < 0.02) G:F. Carcass yield, hot carcass weight, and backfat depth decreased (linear, P < 0.03) whereas percentage lean increased (linear, P < 0.01) with increasing soybean hulls. Pigs fed ground soybean hulls had increased backfat depth (P < 0.01) and decreased (P < 0.01) percentage lean and fat-free lean index. In summary, increasing soybean hulls up to 20% decreased G:F in nursery and finishing pigs, whereas pelleting nursery diets improved ADG and eliminated the negative effect of increasing soybean hulls on G:F. Grinding soybean hulls reduced growth performance in nursery and finishing pigs.

Effects of added fat on growth performance of finishing pigs sorted by initial weight.

Two studies were conducted to determine whether dietary fat fed to pigs of different weight categories differentially influences growth performance. Both experiments were conducted in a 2 × 3 factorial arrangement with main effects of dietary fat addition (0 or 6% choice white grease) and sort weight category (HEAVY, LIGHT, or MIXED). In experiment 1, 1,032 pigs (initially 30.7 kg) were individually weighed and sorted into two body weight (BW) groups with one group consisting of pigs greater than median BW and the other group less than median BW. Pens were then formed by randomly selecting pigs: 1) only from heavy group (HEAVY), 2) only from light group (LIGHT), or 3) from both heavy and light groups to create a normal distribution around barn BW mean (simulation of unsorted pigs; MIXED). In experiment 2, 1,176 pigs (initially 35.1 kg) were visually sorted into BW groups and assigned to HEAVY, LIGHT, and MIXED pen weight categories. Overall in experiment 1, adding 6% dietary fat increased average daily gain (ADG) of LIGHT pigs, but not HEAVY pigs (HEAVY vs. LIGHT × fat interaction, P = 0.03), but increased (P < 0.05) ADG regardless of sort category in experiment 2. In both experiments, HEAVY pigs had greater (P < 0.05) overall ADG and average daily feed intake (ADFI), but decreased (P < 0.05) G:F compared with LIGHT pigs. However, when HEAVY and LIGHT treatment groups were combined, growth performance and carcass characteristics were similar to MIXED pigs. Sorting decreased coefficient of variation (CV) of final BW but did not affect CV of ADG. In conclusion, because adding fat to the diets of lightweight pigs improved ADG in both experiments, dietary fat could be used selectively in the barn to increase the weight of the lightest 50% of the pigs. However, the sorting pigs into light and heavy weight groups did not improve growth performance or carcass characteristics.

Standardized total tract digestible phosphorus requirement of 24- to 130-kg pigs1,2.

A study was conducted to determine the standardized total tract digestible phosphorus (STTD P) requirement for 24- to 130-kg finishing pigs housed under commercial conditions. A total of 1,130 barrows and gilts (PIC 359 × 1050, Hendersonville, TN; initially 24.2 kg) were used, with 26 to 27 pigs per pen with 7 replicates per treatment. Pens of pigs were allotted to treatments in a randomized complete block design with body weight (BW) as the blocking factor. The dietary treatments were fed in 4 phases and were formulated to contain 80%, 90%, 100%, 115%, 130%, and 150% of the National Research Council (NRC) requirement estimate for finishing pigs within each phase. Weight ranges for each phase were: 27 to 49, 49 to 76, 76 to 90, and 90 to 130 kg. Treatments were achieved by increasing the amount of monocalcium phosphate at the expense of corn in the diet with no added phytase. All diets were formulated to contain a similar 1.14:1 to 1.16:1 total Ca:P ratio across treatments in all phases. Increasing STTD P resulted in a quadratic response (P < 0.05) in average daily gain (ADG), gain-to-feed ratio (G:F), and final BW. The greatest improvement was observed with STTD P at 130% of NRC for ADG and final BW and at 115% STTD P for G:F. Average daily feed intake increased linearly (linear, P < 0.05) with the inclusion of STTD P. Increasing STTD P resulted in an increase (quadratic, P < 0.05) in hot carcass weight (HCW) and carcass ADG with the greatest response observed with STTD P at 130% of NRC. There was a marginally significant response (quadratic, P < 0.10) in carcass G:F, with the greatest improvement with STTD P at 115% of NRC. Carcass yield decreased (linear, P < 0.05) with increasing STTD P, while there was a marginally significant (linear, P < 0.10) decrease in backfat and increase in fat-free lean. At the end of the study, a metacarpal was collected and analyzed for bone ash. Increasing STTD P resulted in an increase (linear, P < 0.05) in bone ash weight and percentage ash. For ADG and G:F, the quadratic model demonstrated the best fit. The maximum response in ADG and G:F was estimated at 122% and 116% of NRC STTD P, respectively. The broken-line linear model best fit the data for percentage bone ash, with a plateau achieved at 131% of the NRC STTD P. In conclusion, the estimated STTD P requirement of 24 to 130 kg ranged from 116% to 131% of the NRC publication (2012) requirement estimate.

Effects of standardized total tract digestible phosphorus on growth performance of 11- to 23-kg pigs fed diets with or without phytase1,2.

Two experiments were conducted to determine the standardized total tract digestible phosphorus (STTD P) requirement for 11- to 23-kg nursery pigs fed diets with or without phytase. A total of 1,080 and 2,140 pigs (PIC 359 × Camborough, Hendersonville, TN; initially 11.4 ± 0.29 and 11.1 ± 0.24 kg) were used in Exp. 1 and Exp. 2, respectively. There were 23 to 27 pigs per pen with 6 and 12 replicate pens per treatment in Exp. 1 and Exp. 2, respectively. After weaning, pigs were fed a common pelleted diet with 0.45% STTD P for 7 d, and a common phase 2 meal diet with 0.40% STTD P for 14 d in Exp. 1 and 18 d in Exp. 2. Pens of pigs were then allotted to dietary treatments in a randomized complete block design with body weight (BW) as the blocking factor. In Exp. 1, dietary treatments consisted of 0.26%, 0.30%, 0.33%, 0.38%, 0.43%, 0.48%, and 0.53% STTD P. Treatments were achieved with the inclusion of monocalcium phosphate at the expense of corn. In Exp. 2, diets contained 1,000 phytase units (FYT; Ronozyme Hiphos 2500, DSM Nutritional Products, Inc., Parsippany, NJ) with assumed release value 0.132% STTD P, and treatments consisted of 0.30%, 0.33%, 0.38%, 0.43%, 0.48%, 0.53%, and 0.58% STTD P. These STTD P concentrations included the expected phytase release of 0.132% STTD P. In both experiments, a similar 1.17:1 Ca:P ratio was maintained across treatments. Statistical models included linear model (LM), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). In Exp. 1, increasing STTD P increased (linear, P < 0.001) ADG, ADFI, G:F, final BW, and grams of STTD P intake per day and per kilogram of gain. There was also a marginal quadratic response for G:F (P < 0.066). In Exp. 2, ADG and G:F increased quadratically (P < 0.05), whereas ADFI increased linearly (P = 0.060) with increasing STTD P. The BLL and QP model provided similar fit to G:F in Exp. 1, estimating the requirement for maximum G:F at 0.34% and 0.42%, respectively. The BLL was the best fitting model for ADG and G:F in Exp. 2, estimating the breakpoint at 0.40% and 0.37% STTD P, respectively. The BLL and BLQ models estimated the breakpoint for ADG as a function of STTD P intake in grams per day at 2.92 and 3.02 g/d, respectively. These data provide empirical evidence that for 11- to 23-kg pigs, the NRC (2012) accurately estimates the STTD P requirement on a g/d basis. As a percentage of the diet, the STTD P requirement for diets without or with 1,000 FYT added phytase ranged from 0.34% to 0.42%.

Optimal dietary standardized ileal digestible lysine and crude protein concentration for growth and carcass performance in finishing pigs weighing greater than 100 kg1,2.

Three experiments were conducted to determine the optimal dietary standardized ileal digestible (SID) lysine and CP concentrations for finishing pigs over 100 kg BW. In Exp. 1, 253 pigs (DNA 600 × 241, initially 102.0 kg) were used in a 23-d trial with 7 to 8 pigs per pen and 8 pens per treatment. Dietary treatments contained 4 SID lysine concentrations (0.45, 0.55, 0.65, or 0.75%). To formulate the experimental diets, a corn-soybean meal diet with 0.45% SID lysine was formulated without L-lysine HCl. Then, a corn-soybean meal diet containing 0.75% SID lysine was formulated including 0.23% L-lysine HCl. The 0.45 and 0.75% SID lysine diets were blended to provide the 0.55 and 0.65% SID lysine diets. Increasing SID lysine increased (quadratic, P < 0.05) ADG and ADFI with pigs fed 0.55% SID lysine having the greatest final BW. Marginal improvements in gain:feed (G:F; quadratic, P = 0.058) and carcass yield (linear, P = 0.051) and reduction in backfat (quadratic, P = 0.074) were also observed with increasing SID lysine. The quadratic polynomial models predicted maximum ADG and G:F at 0.62 and 0.63% SID lysine, respectively. The broken-line linear model predicted no further improvement in G:F over 0.55% SID lysine. In Exp. 2, 224 pigs (PIC 327 × 1050, initially 109.4 kg) were used in a 20-d trial with 7 pigs per pen and 7 to 8 pens per treatment. Dietary treatments included 4 concentrations of CP (10, 11, 12, or 13%) that were formed by reducing the amount of L-lysine HCl in a corn-soybean meal diet. Increasing CP increased (linear, P < 0.05) ADG and ADFI with the greatest responses observed in pigs fed the diet with 12% CP. Increasing dietary CP also improved (linear, P < 0.05) G:F, final BW, and hot carcass weight (HCW). In Exp. 3, 238 pigs (DNA 600 × 241, initially 111.8 kg) were used in a 26-d trial with 7 to 8 pigs and 6 pens per treatment. Dietary treatments included 5 concentrations of CP (9, 10, 11, 12, or 13%). Increasing CP improved (quadratic, P < 0.05) ADG and G:F with the greatest response observed in pigs fed 13% CP. Increasing CP marginally increased (quadratic, P < 0.074) HCW, with the greatest response observed in pigs fed 12% CP. In conclusion, the SID lysine requirement for pigs from 100 to 122 kg was 0.55 to 0.63% depending on the response criteria with performance maximized with diets containing 12 to 13% CP.

Effects of Tylosin Administration Routes on the Prevalence of Antimicrobial Resistance Among Fecal Enterococci of Finishing Swine.

Antibiotics can be administered orally or parenterally in swine production, which may influence antimicrobial resistance (AMR) development in gut bacteria. A total of 40 barrows and 40 gilts were used to determine the effects of tylosin administration route on growth performance and fecal enterococcal AMR. The antibiotic treatments followed Food and Drug Administration label directions and were as follows: (1) no antibiotic (CON), (2) 110 mg tylosin per kg feed for 21 d (IN-FEED), (3) 8.82 mg tylosin per kg body weight through intramuscular injection twice daily for the first 3 d of each week for 3 weeks (IM), and (4) 66 mg tylosin per liter of drinking water (IN-WATER). Antibiotics were administered during d 0 to 21 and all pigs were then fed the CON diet from d 21 to 35. Fecal samples were collected on d 0, 21, and 35. Antimicrobial susceptibility was determined by microbroth dilution method. No evidence of route × sex interaction (p > 0.55) was observed for growth performance. From d 0 to 21, pigs receiving CON and IN-FEED had greater (p < 0.05) average daily gain (ADG) than those receiving IM, with the IN-WATER group showing intermediate ADG. Pigs receiving CON had greater (p < 0.05) gain-to-feed ratio (G:F) than IM and IN-WATER, but were not different from pigs receiving IN-FEED. Overall, enterococcal isolates collected from pigs receiving IN-FEED or IM were more resistant (p < 0.05) to erythromycin and tylosin than CON and IN-WATER groups. Regardless of administration route, the estimated probability of AMR to these two antibiotics was greater on d 21 and 35 than on d 0. In summary, IM tylosin decreased ADG and G:F in finishing pigs, which may be because of a response to the handling during injection administration. Tylosin administration through injection and feed resulted in greater probability of enterococcal AMR to erythromycin and tylosin compared with in-water treatment.

Effects of increasing copper from tri-basic copper chloride or a copper-methionine chelate on growth performance of nursery pigs.

A total of 2,117 pigs were used in two 35-d growth experiments to determine the effects of increasing added Cu from tri-basic copper chloride (TBCC) or a Cu-methionine chelate (Cu-chelate) on nursery pig growth performance. In experiment 1, 1,452 pigs (350 barrows [DNA 200 × 400; initially 5.9 ± 0.17 kg] in group 1 and 1,102 pigs [PIC 1050 × 280; initially 6.0 ± 0.26 kg] in group 2) were weaned at approximately 21 d of age. In experiment 2, 665 pigs (350 barrows, DNA 200 × 400; initially 6.4 ± 0.19 kg, in group 3 and 315 pigs, DNA 241 × 600; initially 5.2 ± 0.49 kg, in group 4) were weaned at approximately 21 d of age. Pigs in groups 1, 2, and 3 were fed a common starter diet for 7 d and pigs in group 4 were fed a common diet for 5 d after weaning before starting experiments. On d 0 of each experiment, pens of pigs were blocked by body weight (BW) and assigned to 1 of 7 dietary treatments. Treatments were arranged as a 2 × 3 factorial plus one control diet, with main effects of Cu source (TBCC vs. Cu-chelate) and level. Copper levels were 50, 100, or 150 mg/kg in experiment 1 and 75, 150, or 225 mg/kg in experiment 2. Diets were corn-soybean meal-based and fed in meal form in two phases (d 0 to 14 and 14 to 35). In experiment 1 from d 0 to 35, there was a Cu source × level interaction (linear, P < 0.05) for average daily gain (ADG) and d 35 BW where the magnitude of improvement with increasing Cu was greater in pigs fed Cu-chelate compared to those fed TBCC. Increasing added Cu increased (linear, P < 0.01) average daily feed intake (ADFI) and gain:feed (G:F). Although Cu source did not influence G:F, pigs fed Cu from Cu-chelate had greater (P ≤ 0.01) ADG and ADFI than those fed Cu from TBCC. In experiment 2, from d 0 to 35, there were no evidence for Cu source × level interactions. Increasing Cu increased (linear, P < 0.05) ADG and final BW. The increase in ADG combined with unaffected ADFI resulted in marginally increased G:F (linear, P = 0.052). In summary, these results suggest that increasing dietary Cu from TBCC or a Cu-chelate improved overall ADG, and d 35 BW in nursery pigs and Cu source has potential to influence nursery pig performance.

Evaluation of dietary electrolyte balance on nursery pig performance.

Increasing dietary electrolyte balance (dEB) has been reported to linearly improve pig growth performance up to approximately 200 to 250 mEq/kg. However, recent data indicate that increasing dietary dEB reduced growth performance of nursery pigs. To attempt to solve this discrepancy, a total of 2,880 weanling pigs (327 × 1,050; PIC, Hendersonville, TN; 5.2 kg initial BW) were used to determine the effects of increasing dEB on nursery pig performance. Pens of pigs were blocked by BW and gender on arrival. Within block, pens were randomly assigned to one of four dietary treatments. There were 30 pigs per pen (60 pigs per double-sided feeder) and 12 replications (feeder) per treatment. Dietary treatments were fed in two phases. The phase 1 diet was based on corn-soybean meal, contained dried distillers grains with soblubles (DDGS), spray-dried whey, and specialty protein sources, and was fed from days 0 to 8. The phase 2 (days 8 to 21) diets contained corn, soybean meal, and DDGS with reduced amounts of specialty protein sources. Dietary electrolyte balance was determined using the following equation: dEB = [(Na × 434.98) + (K × 255.74) - (Cl × 282.06)] mEq/kg. The dEB of the four phase 1 diets were 84, 137, 190, and 243 mEq/kg, and dEB of the four phase 2 diets were 29, 86, 143, and 199 mEq/kg. After feeding experimental diets for 21 day, a common, commercial corn-soybean meal diet was fed to all pigs from days 21 to 35 and contained a dEB of 257 mEq/kg. During days 0 to 8, increasing dEB increased (quadratic, P < 0.05) ADG, ADFI, and G:F. From days 8 to 21, increasing dEB improved ADG (quadratic, P = 0.022) and ADFI (linear, P = 0.001), resulting in an improvement (quadratic, P = 0.001) in G:F. Overall (days 0 to 21), increasing dEB increased (linear, P < 0.05) ADG, ADFI, and improved (quadratic, P < 0.001) G:F. When a common diet was fed to all pigs from days 21 to 35, there was a linear reduction in ADG and G:F with increasing dietary dEB, but no effect of ADFI. For the overall nursery period (days 0 to 35), increasing dEB from days 0 to 21 increased (linear, P < 0.001) ADG and final BW, which was the result of increased (quadratic, P < 0.05) G:F and marginally greater (linear, P = 0.077) ADFI. In conclusion, increasing dietary dEB up to 243 and 199 mEq/kg (in phases 1 and 2, respectively) in nursery diets improved growth performance of weanling pigs.

Strategy to blend leftover finisher feed to nursery pigs in a wean-to-finish production system.

In wean-to-finish pig production, leftover finisher feed from the previous group is commonly blended with nursery diets as weanling pigs enter the facility. Two experiments were conducted to evaluate feeding the last finisher diet to nursery pigs. The timing (phase) and dose were evaluated. Each experiment used 1,260 pigs from two commercial research rooms with 21 pigs per pen and 30 pens per room (15 pens per treatment). Pigs were fed commercial nursery diets in a five-phase feeding program, and phase changes were based on a feed budget. In experiment 1, pens of pigs (initially 5.83 kg) were blocked by body weight, gender, and room and allotted to one of four treatments. Treatments included standard nursery diets throughout (control) or standard diets with 2.5 kg/pig of the last finisher feed blended at the beginning of phase 2, 3, or 4. Growth responses during the intermediate periods were promptly decreased (P < 0.05) once the finisher feed was introduced regardless of phase in which it was blended. However, during the overall nursery period, blending the finisher diet into phase 2 decreased (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI), but did not affect gain:feed ratio (G:F), compared with control pigs or those that had blended diet in phase 4 with blending of phase 3 diet intermediate. In experiment 2, weaned pigs were fed common phase 1 and 2 diets before the start of the experiment. At the beginning of phase 3, pens of pigs (initially 10.6 kg) were blocked by body weight and room and allotted to one of four treatments. Treatments consisted of a dose-titration of blending increasing amounts of finisher feed (0, 1.25, 2.50, and 3.75 kg/pig) into the phase 3 nursery diet. Overall, blending increasing amounts of the last finisher feed with phase 3 nursery diet decreased ADG (linear, P = 0.050) and tended to decrease (linear, P < 0.07) ADFI and final body weight. However, there was no evidence for difference in overall G:F. In conclusion, blending finisher feed into the early nursery diets decreased overall ADG and ADFI; however, pigs greater than 11 kg had improved ability to compensate for the negative effects of blending the last finisher feed on overall growth performance. Nevertheless, increasing the amounts of finisher feed fed to 11-kg pigs from 0 to 3.75 kg/pig resulted in a linear decrease in overall ADG and ADFI. Economic analysis indicated no change in income-over-feed-cost due to the timing and dose of blending finisher feed into nursery diets.

Regression analysis to predict the impact of dietary neutral detergent fiber on carcass yield in swine.

Research has shown that carcass yield in swine is reduced when ingredients with high neutral detergent fiber (NDF) content. Carcass yield reduction from feeding high-fiber ingredients results from an increase in the weight of intestinal contents. NDF has been shown to result in the digestive contents to swell in the large intestine by absorbing water thus increasing the fecal volume in the large intestine. Considering the financial implications of changing carcass yield, the objective of this project was to develop a regression equation to estimate carcass yield from dietary NDF and strategies where high-NDF ingredients are taken out of the diet in the last dietary phases before slaughter (withdrawal period; WP). Data from 8 experiments (43 observations) originated from 6 journal articles and 1 technical memo were used to develop the regression equation. The WP of high NDF ingredients was either none or ranged from 5 to 63 d in the experiments. Treatment diets of each trial were reformulated to obtain dietary nutrient content using the NRC ingredient library (NRC, Nutrient requirements of swine. 11th ed, 2012). Composition of experimental diets was used to calculate dietary net energy, crude protein, crude fiber, NDF, and acid detergent fiber in the last two dietary phases. These dietary compositions along with the number of days of WP were used to develop regression equations. The model was determined using a step-wise selection procedure starting with guided forward selection through individual predictor variables, with a statistical significance at P < 0.05 used to determine inclusion of terms in the final model. The regression analysis showed that WP, NDF level in the dietary phase prior to the final phase (NDF1), NDF level in the last dietary phase before marketing (NDF2), and the interaction between NDF2 and WP were the most important variables in the dataset to predict carcass yield. The resulting regression equation was as follows: carcass yield, % = 0.03492 ± 0.02633 × WP (d) - 0.05092 ± 0.02862 × NDF1 (%) - 0.06897 ± 0.02931 × NDF2 (%) - 0.00289 ± 0.00216 × (NDF2 [%] × WP [d]) + 76.0769 ± 1.33730. In conclusion, high levels of NDF up to slaughter had a negative impact on carcass yield. Increasing the length of the WP improved carcass yield; however, the effect of WP was dependent on the level of NDF2. The equation herein provides a tool to estimate of the impact of dietary NDF on carcass yield.

The effects of soybean hulls level, distillers dried grains with solubles, and net energy formulation on nursery pig performance.

Four experiments were conducted to investigate the effects of increasing dietary soybean hulls without or with distillers dried grains with solubles (DDGS) and net energy (NE) formulation on nursery pig performance. In experiment 1, a total of 210 nursery pigs (initially 6.6 ± 0.1 kg) were used in a 34-d study. Pigs were fed one of five diets that contained increasing soybean hulls (0%, 5%, 10%, 15%, and 20%). Diets were not balanced for NE. Increasing soybean hulls decreased (linear, P < 0.01) average daily gain (ADG) and gain:feed ratio(G:F), and tended to decrease average daily feed intake (ADFI; quadratic, P < 0.10). In experiment 2, 210 nursery pigs (initially 13.6 ± 0.1 kg) were used in a 20-d study to determine the effect of equal NE formulation in diets with soybean hulls. Pigs were fed one of five diets containing 0% (control), 10%, or 20% soybean hulls either balanced to contain equal NE to the control diet or not balanced for energy. Diets containing 10% and 20% soybean hulls with balanced NE contained 3.60% and 7.15% added soybean oil, respectively. Increasing soybean hulls decreased (linear, P < 0.01) ADG regardless of formulation method. Pigs fed increasing soybean hulls without added fat had decreased (linear, P < 0.01) G:F. Increasing soybean hulls in diets with balanced NE decreased (linear, P < 0.02) ADFI, but did not affect G:F. In experiment 3, 600 pigs (initially 6.8 ± 0.1 kg) were used in a 42-d study. Pigs were fed 1 of 10 diets containing 0%, 3%, 6%, 9%, or 12% soybean hulls without or with DDGS (15% from d 0 to 14, 30% from d 15 to 42). Feeding DDGS reduced (P < 0.04) ADG and ADFI, and tended to increase (P < 0.06) G:F. Increasing soybean hulls decreased G:F quadratically (P < 0.03) in diets without DDGS, but decreased G:F linearly (P < 0.01) in diets with DDGS (soybean hulls × DDGS interaction, P < 0.05). In experiment 4, 304 barrows (initially 11.7 ± 0.2 kg) were used in a 21-d study. Pigs were fed one of eight diets containing 0%, 5%, 10%, or 15% soybean hulls with or without 20% DDGS. No soybean hull × DDGS interactions were observed. Increasing soybean hulls tended to decrease (linear, P < 0.08) G:F. In conclusion, feeding low levels of soybean hulls did not affect nursery pig performance but more than 5% soybean hulls, with or without DDGS, decreased G:F. Formulating diets containing soybean hulls on an equal NE basis eliminated the negative effects on G:F, but the NE (1,003 kcal/kg) of soybean hulls used in this study was underestimated.

Effects of increasing copper from either copper sulfate or combinations of copper sulfate and a copper-amino acid complex on finishing pig growth performance and carcass characteristics.

A total of 1,089 pigs (PIC 280 × 1050; initially 37.3 ± 2.8 kg) were used to determine the effects of increasing Cu provided from either CuSO4 alone or a 50:50 blend of CuSO4 and a Copper-amino acid complex (Cu-AA) on growth performance and carcass characteristics of finishing pigs. Pens of pigs were blocked by body weight; within blocks, pens were randomly allotted to one of six dietary treatments. The six dietary treatments consisted of a control diet which contained 17 mg/kg Cu from CuSO4 from the trace mineral premix, or the control diet with either added CuSO4 to provide 70 and 130 mg/kg total Cu or a 50:50 blend of Cu from CuSO4 and Cu-AA (CuSO4/Cu-AA blend) to provide 70, 100, and 130 mg/kg total Cu. Experimental diets were corn-soybean meal-dried distillers grains with solubles-based and fed in meal form in five phases (approximately 37 to 46, 46 to 63, 63 to 77, 77 to 103, and 103 to 129 kg body weight). From d 0 to 43, neither Cu source nor level influenced growth performance. From d 43 to 105, average daily feed intake (ADFI) decreased (P = 0.037) for pigs fed the CuSO4/Cu-AA blend compared to those fed added Cu from CuSO4 alone. Gain:feed ratio (G:F) tended to be improved (linear, P = 0.056) as Cu concentration increased. Overall, d 0 to 105, neither Cu level nor source influenced average daily gain (ADG). Pigs fed 70 or 130 mg/kg total added Cu from the CuSO4/Cu-AA blend had lower (P = 0.045) ADFI but G:F tended to be improved (P = 0.051) compared with those fed the same amount of total Cu from only CuSO4. Owing to the decreased ADFI and improved G:F of pigs fed the CuSO4/Cu-AA blend, carcass G:F also improved (P = 0.033) compared with those fed added Cu from CuSO4 alone. In conclusion, providing a 50:50 blend of CuSO4 and Cu-AA improved G:F on both a live and carcass weight basis compared to CuSO4 alone with no differences in ADG or carcass ADG observed.

Effects of sodium and chloride source and concentration on nursery pig growth performance.

Three studies were conducted to determine the effects of source and concentration of Na and Cl on pig growth performance from 7 to 12 kg. In all three experiments, pigs were fed a common diet (0.33% Na and 0.77% Cl) for 7 or 8 d after weaning then randomly assigned to dietary treatments. In Exp. 1, 360 mixed-sex pigs were used in a 14-d study with 15 replications per treatment and six pigs per pen. Treatments included a 10% dried whey diet with 0.60% added salt (0.37% Na and 0.75% Cl); or three diets with 7.2% crystalline lactose with either: 0.35% added salt (0.18% Na and 0.47% Cl); 0.78% added salt (0.35% Na and 0.72% Cl); or 1.15% NaHCO3 and 0.40% KCl (0.35% Na and 0.45% Cl). Pigs fed the 0.78% added salt-lactose diet had greater (P < 0.05) ADG than pigs fed the 0.35% added salt-lactose diet, with others intermediate. In Exp. 2, 360 barrows were used in a 14-d study with 12 replications per treatment and five pigs per pen. Treatments included two added salt diets (providing 0.13% Na and 0.35% Cl or 0.35% Na and 0.68% Cl), three diets with Na and Cl provided by KCl and NaHCO3 (0.13%, 0.35%, or 0.57% Na and 0.50% Cl), or a diet with NaHCO3 and CaCl2 (0.35% Na and 0.50% Cl). Regardless of Na source, ADG and ADFI increased (quadratic, P < 0.05) as dietary Na increased from 0.13% to 0.35%, with no further benefits observed thereafter. There was no evidence for differences among pigs fed NaCl or NaHCO3 nor evidence for differences among pigs fed the different Na and Cl sources at similar concentrations. In Exp. 3, 300 pigs were used in a 21-d trial with 10 replications per treatment and five pigs per pen. Treatments included a control diet with added salt to provide 0.33% Na and 0.55% Cl or five diets with 0.33 % Na and added KCl to provide 0.09, 0.21, 0.32, 0.45, or 0.55% Cl. ADG and G:F increased (quadratic, P < 0.035) as Cl increased from 0.09% to 0.32%. Pigs fed the control diet (added salt) and the 0.55% Cl diet had similar ADG. For ADG and ADFI, the broken line linear model indicated a breakpoint of 0.23% Cl. For G:F, the quadratic polynomial model suggested the maximum at 0.38% Cl. In conclusion, 7 to 12 kg pigs fed diets that contained at least 0.35% Na and 0.38% Cl had greater ADG and G:F compared to pigs fed diets with lower concentrations and minimal effects were observed among the sources of Na or Cl used in these studies.

Relaxin Family Member Insulin-Like Peptide 6 Ameliorates Cardiac Fibrosis and Prevents Cardiac Remodeling in Murine Heart Failure Models.

BACKGROUND: The insulin/insulin-like growth factor/relaxin family represents a group of structurally related but functionally diverse proteins. The family member relaxin-2 has been evaluated in clinical trials for its efficacy in the treatment of acute heart failure. In this study, we assessed the role of insulin-like peptide 6 (INSL6), another member of this protein family, in murine heart failure models using genetic loss-of-function and protein delivery methods. METHODS AND RESULTS: Insl6-deficient and wild-type (C57BL/6N) mice were administered angiotensin II or isoproterenol via continuous infusion with an osmotic pump or via intraperitoneal injection once a day, respectively, for 2 weeks. In both models, Insl6-knockout mice exhibited greater cardiac systolic dysfunction and left ventricular dilatation. Cardiac dysfunction in the Insl6-knockout mice was associated with more extensive cardiac fibrosis and greater expression of fibrosis-associated genes. The continuous infusion of chemically synthesized INSL6 significantly attenuated left ventricular systolic dysfunction and cardiac fibrosis induced by isoproterenol infusion. Gene expression profiling suggests liver X receptor/retinoid X receptor signaling is activated in the isoproterenol-challenged hearts treated with INSL6 protein. CONCLUSIONS: Endogenous Insl6 protein inhibits cardiac systolic dysfunction and cardiac fibrosis in angiotensin II- and isoproterenol-induced cardiac stress models. The administration of recombinant INSL6 protein could have utility for the treatment of heart failure and cardiac fibrosis.

Effect of diet type and added copper on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs.

A total of 757 pigs (PIC 337 × 1050; initially 27.6 kg BW) were used in a 117-d experiment to determine the effects of added Cu from tribasic copper chloride and diet type on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs. Pens of pigs were allotted to 1 of 4 dietary treatments, balanced on average pen weight in a randomized complete block design with 26 to 28 pigs per pen and 7 replications per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of diet type, a corn-soybean meal-based diet (corn-soy) or a high by-product diet (by-product) with 30% distillers dried grains with solubles (DDGS) and 15% bakery meal, and added Cu (0 or 150 mg/kg added Cu). There were no Cu × diet type interactions for growth performance. Overall, neither added Cu nor diet type influenced growth performance. However, caloric efficiency was decreased (P = 0.001) for pigs fed the by-product diet compared to the corn-soy diet. Pigs fed the by-product diet had decreased (P < 0.05) carcass yield and carcass G:F) and marginally decreased (P < 0.07) HCW and carcass ADG compared to pigs fed the corn-soy diet. A Cu × diet type interaction (P < 0.05) existed for DM and GE digestibility during the early finishing period as added Cu improved (P < 0.05) digestibility of DM and GE in the corn-soy diet, but not in the by-product diet. During the late finishing period, added Cu marginally increased (P = 0.060) DM and GE digestibility while pigs fed the by-product diet had decreased DM and GE digestibility (P = 0.001) compared to those fed the corn-soy diet. For gut morphology, pigs fed added Cu had decreased crypt depth (P = 0.017) in the distal small intestine compared to those fed no added Cu. Furthermore, relative mRNA expression of intestinal fatty acid binding protein (iFABP) was decreased (P = 0.032) in pigs fed added Cu compared to those fed no added Cu. In summary, adding 150 mg/kg added Cu or including 30% DDGS and 15% bakery meal into a corn-soy diet did not influence growth performance. However, HCW ADG and HCW G:F were reduced in pigs fed the by-product diet compared to the corn-soy diet. Only minor differences in gut morphology or mRNA expression were observed from feeding diets with high levels of Cu or by-products compared to a corn-soy diet.

Effect of standardized ileal digestible lysine and added copper on growth performance, carcass characteristics, and fat quality of finishing pigs.

Two, 120-d, experiments were conducted to determine the effects of standardized ileal digestible (SID) lysine (Lys), added Cu (tribasic copper chloride, Intellibond C; Micronutrients, Inc., Indianapolis, IN), and duration of Cu supplementation on growth performance, carcass characteristics, and fat quality in finishing pigs. In Exp. 1, 1,248 pigs (PIC 337 × 1050; initially 29.0 kg) were allotted to one of six dietary treatments, balanced on average pen weight in a randomized complete-block design with 26 pigs per pen and eight replications per treatment. Treatments were arranged in a 3 × 2 factorial with main effects of SID Lys (85, 92.5, and 100% of the estimated requirement) and added Cu (0 or 150 mg/kg). There were no Cu × SID Lys interactions observed for growth performance or liver Cu concentrations. Increasing SID Lys increased (linear, P < 0.05) ADG, feed efficiency (G:F), final weight, and HCW. Pigs fed 150 mg/kg added Cu had marginally increased (P < 0.10) ADG, G:F, and final weight. Liver Cu concentrations were greater (P = 0.001) in pigs fed added Cu. A marginal Cu × Lys interaction (P = 0.052) was observed for jowl fat iodine value (IV) as increasing SID Lys in pigs fed added Cu increased IV, but decreased IV in pigs not fed added Cu. For Exp. 2, 1,267 pigs (PIC 337 × 1,050; initially 26.4 kg) were allotted to one of eight dietary treatments arranged in a split-plot design. Whole-plot treatments included SID Lys (92.5 or 100% of the estimated requirement) and within each Lys level, there was a 2 × 2 factorial arrangement of treatments with either 0 or 150 mg/kg added Cu and two feeding durations (60 or 120 d). Added Cu did not affect growth performance. Pigs fed 100% of the SID Lys requirement had increased (P < 0.05) ADG, G:F, and final weight compared with those fed 92.5%. A Cu × SID Lys interaction (P < 0.05) was observed for carcass yield and backfat depth. Pigs fed 92.5% SID Lys had increased carcass yield and decreased backfat depth with added Cu; however, pigs fed 100% SID Lys had decreased carcass yield and increased backfat depth with added Cu. Hot carcass weight was increased (P < 0.05) by feeding 100% SID Lys and was marginally (P < 0.10) increased by adding Cu to the diets. In summary, the growth response to added Cu was inconsistent between experiments; however, increasing SID Lys improved growth performance and carcass characteristics.