The impact of marker selection, in-line near-infrared spectroscopy (NIR), and feed mix time on the coefficient of variation (mix uniformity), body weight uniformity and broiler growth performance during the starter, grower, and finisher periods.

Most feed manufacturers in the United States use the same mixing time (and thus mix uniformity) throughout the growing period regardless of age and consumption patterns. However, research evaluating the optimum mixing time requirements and novel analysis methods, such as in-line near-infrared (NIR) spectroscopy, on the coefficient of variation (CV) and growth performance of broilers throughout the production phases is sparse. Two experiments were conducted to determine the effects of marker selection, in-line NIR, and varying mix times on mix uniformity, broiler growth performance, and body weight uniformity from 1 to 42 d of age. Feed was manufactured utilizing a 1,815-kg counterpoise ribbon mixer. In both experiments, feed was mixed for 4.5 min (3 min dry mix and 90 s of wet mix) and 30 s (0 s dry mix and 30 s wet mix) to obtain a standard mix (SM) and an abbreviated mix (AM), respectively. Experiment 1 constituted a 2 × 2 × 4 factorial arrangement of 2 mix times, (4.5 and 0.5 min), 2 batch sizes (908 and 1,815 kg), and 4 methodologies to evaluate mixer performance (sodium chloride, Microtracers (Red#40 and Blue#40), and in-line NIR). In experiment 2, broilers received different mix time combinations: 1) SM from 1 to 42 d, 2) SM from 1 to 28 d and AM from 28 to 42 d, 3) SM from 1 to 14 d and AM from 14 to 42 d, and 4) AM from 1 to 42 d. In both experiments, selecting a single source marker provided a more accurate estimation of mixer CV in SM and AM diets (P < 0.05). In experiment 2, mix time did not influence BW, feed intake (FI), FCR, or individual bird BW CV from 1 to 42 d of age (P > 0.05). These data indicated that mixer CV differed depending on total mix time and methodology used and diets with a reduced mix time may not necessarily influence growth performance and BW uniformity during the starter, grower, and finisher periods of broilers.

Effect of methionine chelated Zn and Mn and corn particle size on Large White male turkey live performance and carcass yields.

Most turkey research has been conducted with a regular corn particle size set through phase-feeding programs. This study's first objective was to determine the effect of increasing corn particle size through the feed phases on performance, processing yield, and feed milling energy usage in Large White commercial male turkey production. Zinc (Zn) and manganese (Mn) are essential microminerals for animals' healthy growth. The source in which these elements are supplied to the bird will determine their bioavailability, effect on bird growth, and subsequent environmental impact. This study's second objective was to measure both inorganic and chelated Zn and Mn sources on turkey performance, turkey carcass processing yields, and subsequent litter residues. Twelve hundred Nicolas Select male poults were randomly assigned to 48 concrete; litter-covered floor pens. The experimental design was a completely randomized block design with a 2 × 2 factorial arrangement of 2 sources of minerals (organic blend vs. inorganic) formulated to match breeder recommendations and 2 types of corn mean particle size (coarse corn [1,000-3,500 µm] vs. fine corn [276 µm]). The ASABE S319.4 standard was used to measure corn mean particle size. Bird performance, carcass processing yield, litter content of Zn and Mn, and pellet mill energy consumption were analyzed in SAS 9.4 in a mixed model. There was a reduction of pellet mill energy usage of 36% when coarse corn was added post-pelleting. Birds fed increasing coarse corn mean particle size were 250 g lighter on average in body weight (BW) than birds fed a constant control mean particle size. No difference was found in feed intake (FI) or feed conversion ratio (FCR). Birds fed methionine chelated Zn and Mn blended with inorganic mineral sources were 250 g heavier on average than birds fed only an inorganic source of minerals. In addition, feeding an organic blend of Zn and Mn resulted in greater breast meat yield. Litter from birds fed the control corn mean particle size, and inorganic minerals had a higher concentration of Zn in the litter but were not different when the chelated Zn/Mn were fed. In conclusion, increasing the corn mean particle size and adding it post pellet could save money during feed milling; however, birds might have a slightly lower BW. A combination of inorganic and chelated Zn and Mn may improve performance and increase total breast meat yields.

Effect of pellet quality and biochar litter amendment on male turkey performance.

Bedding (litter) is essential to poultry performance and health and can have an environmental impact after use in the poultry facility such as a soil amendment or as an alternative energy source. Pine shavings are the most common bedding used for turkey production. However, the increase in its price and its increasing scarcity in some areas have created new research opportunities for reusing litter as bedding. Improvement in feed pellet quality has been reported to improve poultry performance. However, the reports for turkeys are limited and dated. This study's objective was to determine how the improvement of feed pellet quality and the use of biochar added to a combination of used turkey brooder house litter and Miscanthus grass as bedding affects turkey performance, small intestine morphology, and ammonia production. Nicolas Select (Aviagen Turkeys, Lewisburg, WV) male poults (816) were randomly assigned to 48 concrete litter floor pens on the day of hatch. The experiment used a completely randomized block design with a 2 × 4 factorial arrangement of treatments: 2 levels of fines in the feed and 4 bedding treatments. The bedding treatments were a constant level of used turkey brooder house litter combined with a varying combination of biochar and Miscanthus grass. Turkey's body weight (BW), body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined. Differences in treatment means were considered to be statistically significant at P ≤ 0.05 using a mixed model in SAS 9.4. Turkeys fed the feed with improved pellet quality had a higher BW from 3 to 17 wk (17.0 ± 0.1 kg) than turkeys fed an increased abundance of fines (16.72 ± 0.1 kg). Turkeys fed feed with increased pellet quality had a lower FI (45.6 vs. 48.1 ± 0.4 kg) and improved FCR (2.20 vs. 2.31 ± 0.01) from 0 to 20 wk. Litter treatment with 20% biochar resulted in higher BW at 20 wk (20.91 ± 0.16 kg) because of increased BWG at 11 wk over the rest of the biochar levels (3.7 ± 0.1 kg). Strategies to reduce the abundance of fines in feed through feed formulation, feed manufacturing, feed transport, and in-house feed management should be considered to increase male turkeys' performance. There may be opportunities to use biochar as a litter amendment to improve turkey health and performance.

Effect of feed form, soybean meal protein content, and Rovabio Advance on poult live performance to 3 wk of age.

Based on research reports, feed characteristics can increase poult growth via several factors. Two rearing experiments (EXP) were conducted to test the effects of feed form and ingredient quality in turkey poults. Bird performance and the duodenum, jejunum, ileum, and cecum morphology were observed in both EXP. Poults were reared in battery cages (48 cages in EXP 1 and 72 cages in EXP 2). Four dietary treatments with differing feed form and function factors were evaluated in EXP 1. A completely randomized block design with a 2 × 2 × 2 factorial arrangement of treatments consisting of 2 levels of fines, 2 soybean meal (SBM) sources, and 2 levels of an enzyme cocktail (Rovabio Advance) was tested in EXP 2. Poult BW, BW gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined in both EXP. Apparent metabolizable energy corrected for nitrogen (AMEn) was determined in EXP 2. Differences were considered to be statistically significant at P ≤ 0.05. Feeding increased feed crumble particle size with fewer fines in the starter feed resulted in an increased BWG accompanied by an increased FI. Reduced feed fines reduced AMEn when the dietary enzyme cocktail was not present. The feed formulation with 60% CP SBM resulted in a lower FI and an improved FCR. The enzyme cocktail interacted synergistically with screening and fed SBM source factors on the AMEn and FCR. It was concluded that both the feed form and quality, as used in this study, affect poult performance.

Efficacy of feed additives to reduce the effect of naturally occurring mycotoxins fed to turkey hen poults reared to 6 weeks of age.

Corn with naturally occurring aflatoxin (AF), wheat with naturally occurring doxynivalenol (DON), and barley with naturally occurring zearalenone (ZEA) were used to make rations for feeding turkey hen poults to 6 weeks of age. Control rations with equal amounts of corn, wheat, and barley were also fed. The control rations did contain some DON while both sets of rations contained ZEA. Within each grain source, there were 4 treatments: the control ration plus 3 rations each with a different feed additive which were evaluated for the potential to lessen potential mycotoxin effects on bird performance and physiology. The additives were Biomin BioFix (2 lb/ton), Kemin Kallsil (4 lb/ton), and Nutriad UNIKE (3 lb/ton). The mycotoxin rations reduced poult body weight (2.31 vs. 2.08 ± 0.02 kg) and increased (worsened) poult feed conversion (1.47 vs. 1.51 ± 0.01) at 6 wk. Feeding the poults the mycotoxin feed also resulted in organ and physiological changes typical of feeding dietary aflatoxin although a combined effect of AF, DON, and ZEA which cannot be dismissed. The feed additives resulted in improved feed conversion to 6 wk in both grain treatment groups. The observed physiological effect of feeding the additives was to reduce relative gizzard weight for both groups and to lessen the increase in relative kidney weight for the birds fed the mycotoxin feed. In conclusion, the feed additives used in this study did alleviate the effect of dietary mycotoxins to some degree, especially with respect to feed conversion. Further studies of longer duration are warranted.

Effects of pelleting conditioner retention time on nursery pig growth performance.

A total of 180 nursery pigs (PIC 327 × 1050; initially 12.6 kg) were used in an 18-d study to determine the effects of pellet mill conditioning parameters and feed form on pig performance. All diets were similar, and different feed processing parameters were used to create experimental treatments. Factors considered were conditioning time (15, 30, or 60 s) and feed form (mash or pelleted). To remove the confounding factor of feed form, pelleted samples were reground to a similar particle size as the mash diet. Treatments included: 1) mash diet without thermal processing (negative control), 2) pelleted diet conditioned for 30 s (positive control), 3) pelleted diet conditioned for 15 s and reground, 4) pelleted diet conditioned for 30 s and reground, and 5) pelleted diet conditioned for 60 s and reground. Pigs were weaned and fed a common acclimation diet for 21 d before the start of the experiment. Growth and feed disappearance were then measured for 18 d. All diets had similar levels of percentage total starch, but thermally processed diets had a 1.67 to 1.87-fold increase in percentage gelatinized starch compared to the mash diet. Average daily gain and G:F did not differ between treatments overall, but pigs fed the positive control pelleted diet had decreased ADFI ( < 0.05) compared to pigs fed all other diets. Preplanned contrasts revealed that pigs fed mash diets tended to have greater ADG ( < 0.10) compared to those fed pelleted and reground diets. This suggests that processing may have had a negative influence on feed utilization, which is further supported by the finding that pigs fed mash diets tended to have greater ADG ( < 0.10) compared to those fed diets that were thermally processed, regardless of regrinding. Considering these results, it was not surprising that pigs fed mash diets had greater ADG and ADFI ( < 0.05) than those fed pelleted diets. When directly comparing diets conditioned at 60 rpm, fed either as whole pellets or reground to mash consistency, pigs fed pelleted diets had improved G:F ( < 0.05) due to lower ADFI ( < 0.05) but similar ADG. The expected improvement in G:F from pelleting (6.8%) was observed but lost when diets were reground to near original mash particle size. This may indicate that diet form from the actual pelleting process impacts G:F more than conditioner retention time.

Effects of feeding cracked corn to nursery and finishing pigs.

Four experiments were conducted to determine the effects of supplementing cracked corn in nursery and finishing pig diets (PIC TR4 × 1050). In Exp. 1, 144 pigs (7.5 kg BW) were used in a 28-d experiment with 6 pigs per pen and 6 pens per treatment. Treatments were corn-soybean meal based in the form of mash, pellets (PCD), and pellets with 100% of the corn ground (PGr; 618 mm) or cracked (PCr; 3444 mm) and blended into the diet after the rest of the formulation had been pelleted. For d 0 to 28, pigs fed mash had increased (P = 0.042) ADFI compared with those fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F compared with pigs fed PGr and PCr. Pigs fed PCr had decreased (P = 0.004) G:F compared with those fed PGr. For Exp. 2, 224 nursery pigs (7.4 kg BW) were used in a 28-d study with 7 pigs per pen and 8 pens per treatment. Treatments were similar to Exp. 1, with 50% of the corn either ground (445 mm) or cracked (2142 mm). For d 0 to 28, pigs fed mash had greater (P < 0.05) ADFI and G:F than pigs fed the PCD diet. Pigs fed the PCD diet had decreased (P = 0.001) ADFI and increased (P = 0.001) G:F compared to those fed PGr and PCr. For Exp. 3, 208 pigs (62.6 kg BW) were used in a 63-d experiment with 13 pigs per pen and 4 pens per treatment. Treatments were corn-soybean meal based with 0, 10, 20, and 40% cracked corn (3549 µm). All treatments were fed in mash form. For d 0 to 63, increasing cracked corn tended to decrease (linear, P = 0.093) G:F and decreased (linear, P = 0.047) carcass yield. Adding up to 40% of cracked corn to a mash diet decreased (P < 0.05) scores for keratinization and ulcers. For Exp. 4, 252 finishing pigs (40 kg BW) were used with 7 pigs per pen and 9 pens per treatment. The treatments were the same as described in Exp. 2. For the 80-d experiment, pigs fed mash had decreased (P < 0.05) ADG, stomach keratinization, and ulcer scores and increased (P < 0.05) yield and loin depth compared with pigs fed the PCD diet. Pigs fed PCD had increased (P < 0.05) ADG and G:F and decreased (P = 0.026) loin depth compared with pigs fed PGr and PCr diets. Pigs fed PCr had increased (P = 0.023) ADG and decreased (P = 0.001) yield compared with pigs fed PGr. Pigs fed PCr had decreased (P < 0.05) stomach keratinization and ulcer scores compared with pigs fed the PCD and PGr diets. In conclusion, pigs fed PCD had the greatest G:F, and PGr and PCr treatments had negative effects on G:F of pigs. Scores for stomach lesions were lowest for pigs fed PCr.

Evaluation of conditioning time and temperature on gelatinized starch and vitamin retention in a pelleted swine diet.

Two key feed processing parameters, conditioning temperature and time, were altered to determine their effects on concentration of gelatinized starch and vitamin retention in a pelleted finishing swine diet. Diet formulation (corn­soybean meal based with 30% distillers dried grains with solubles) was held constant. Treatments were arranged in a 2 × 3 factorial design plus a control with 2 conditioning temperatures (77 vs. 88°C) and 3 conditioner retention times (15, 30, and 60 s). In addition, a mash diet not subjected to conditioning served as a control for a total of 7 treatments. Samples were collected after conditioning but before pelleting (hot mash), after pelleting but before cooling (hot pellet), and after pelleting and cooling (cold pellet) and analyzed for percentage total starch, percentage gelatinized starch, and riboflavin, niacin, and vitamin D3 concentrations. Total percentage starch was increased by greater conditioning temperature (P = 0.041) but not time (P > 0.10), whereas higher temperature and longer time both increased (P < 0.05) percentage gelatinized starch, with increasing time resulting in a linear increase in percentage starch gelatinization (P = 0.013). The interaction between conditioning temperature and time increased percentage gelatinized starch (P = 0.003) but not percentage total starch (P > 0.10). Sample location also affected both percentage total starch and gelatinized starch (P < 0.05), with the greatest increase in percentage gelatinized starch occurring between hot mash and hot pellet samples. As expected, the pelleting process increased percentage gelatinized starch (P = 0.035; 7.3 vs. 11.7% gelatinized starch for hot mash vs. hot pellet samples, respectively), but there was no difference in total starch concentrations (P > 0.10). Finally, neither conditioning temperature nor time affected riboflavin, niacin, or vitamin D3 concentrations (P > 0.10). In summary, both increasing conditioningtemperature and time effect percentage gelatinized starch, but not to the extent of forcing the diet through a pelleting die.

Effect of crude glycerol on pellet mill production and nursery pig growth performance.

The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P

High activity and stability of hammerhead ribozymes containing 2'-modified pyrimidine nucleosides and phosphorothioates.

The influence of chemical modifications on the catalytic activity and stability of a hammerhead ribozyme directed against the long terminal repeat RNA of the human immunodeficiency virus 1 was examined. Previous studies had shown that substitution of all pyrimidine nucleosides by their 2'-fluoro analogs led to an 8-fold decrease in catalytic efficiency in the cleavage reaction compared to the unmodified ribozyme (Heidenreich, O., and Eckstein, F. (1992) J. Biol. Chem. 267, 1904-1909). It is shown here that replacement of the 2'-fluoro-2'-deoxyuridines in the conserved region of this ribozyme, positions 4 and 7, by 2'-amino-2'-deoxyuridines fully restores catalytic activity of the ribozyme. Ribozymes containing these 2'-modifications show an increased stability against RNases present in fetal calf serum and in cell culture supernatant. The stability is increased further by the incorporation of four terminal phosphorothioates as protection against 3'-exonucleases, the degree of which depends on the secondary structure of the ribozyme. Such ribozymes are stable in undiluted fetal calf serum for at least 24 h. The results clearly demonstrate the potential to design stable ribozymes without any loss of catalytic activity.