Dietary iron or inulin supplementation alters iron status, growth performance, intramuscular fat and meat quality in finisher pigs.

Forty LW × L pigs (20 boars and 20 gilts) (51.1 ± 0.41 kg) were allocated to a 2 × 2 × 2 factorial design with the respective factors being supplemental organic iron (Fe, 0 and 500 mg/kg), inulin (In, 0 and 50 g/kg) and sex (boars and gilts). After 5 weeks the animals were transported to an abattoir before slaughter and collection of samples. Serum iron was increased by supplemental Fe (28.4 v. 30.9 µmol/L, P = 0.05), although there was an interaction (P = 0.03) such that pigs fed diets with In had lower serum Fe concentrations than those without In (26.8 v. 32.3 µmol/L). Boars had lower (P < 0.01) haemoglobin (116 vs 125), haematocrit (36.7 v. 39.7%) and erythrocyte (6.6 v. 7.1 × 106/mL) concentrations than gilts. Dietary In increased liveweight gain (795 v. 869 g/d, P < 0.02) and carcass weight (62.9 v. 65.2 kg, P < 0.02). Dietary Fe or In supplementation did not improve muscle Longissimus thoracis et lumborum (LTL) total Fe concentration (P > 0.05). Muscle non-heme Fe concentration was higher in Fe-supplemented pigs (P < 0.04) and gilts (P < 0.05) than their counterparts. Muscle heme Fe concentration was greater (3.04 vs 2.51, P < 0.05) in boars than in gilts. The LTL marbling score was greater (P < 0.01) for In-supplemented pigs, and the response was more notable when Fe and In were fed together. These data show that dietary supplementation of Fe increased serum Fe and muscle non-heme Fe concentrations. Supplementation of In at 5% in the diet of finisher pigs improved liveweight gain and the marbling score of pork.

Animal board invited review: Factors affecting the early growth and development of gilt progeny compared to sow progeny.

Progeny born to primiparous sows farrowing their first litter, often called gilt progeny (GP), are typically characterised by their poorer overall production performance than progeny from multiparous sows (sow progeny; SP). Gilt progeny consistently grow slower, are born and weaned lighter, and have higher postweaning illness and mortality rates than SP. Collectively, their poorer performance culminates in a long time to reach market weight and, ultimately, reduced revenue. Due to the high replacement rates of sows, the primiparous sow and her progeny represent a large proportion of the herd resulting in a significant loss for the pig industry. While the reasons for poorer performance are complex and multifaceted, they may largely be attributed to the immature age at which gilts are often mated and the significant impact of this on their metabolism during gestation and lactation. As a result, this can have negative consequences on the piglet itself. To improve GP performance, it is crucial to understand the biological basis for differences between GP and SP. The purpose of this review is to summarise published literature investigating differences in growth performance and health status between GP and SP. It also examines the primiparous sow during gestation and lactation and how the young sow must support her own growth while supporting the metabolic demands of her pregnancy and the growth and development of her litter. Finally, the underlying physiology of GP is discussed in terms of growth and development in utero, the neonatal period, and the early development of the gastrointestinal tract. The present review concludes that there are a number of interplaying factors relating to the anatomy and physiology of the primiparous sow and of GP themselves. The studies presented herein strongly suggest that poor support of piglet growth in utero and reduced colostrum and milk production and consumption are largely responsible for the underperformance of GP. It is therefore recommended that future management strategies focus on supporting the primiparous sow during gestation and lactation, increasing the preweaning growth of GP to improve their ability to cope with the stressors of weaning, selection of reproductive traits such as uterine capacity to improve birth weights and ultimately GP performance, and finally, increase the longevity of sows to reduce the proportion of GP entering the herd.

Review: Can early-life establishment of the piglet intestinal microbiota influence production outcomes?

The gastrointestinal tract microbiota is involved in the development and function of many body processes. Studies demonstrate that early-life microbial colonisation is the most important time for shaping intestinal and immune development, with perturbations to the microbiota during this time having long-lasting negative implications for the host. Piglets face many early-life events that shape the acquisition and development of their intestinal microbiota. The pork industry has a unique advantage in that the producer has a degree of control over what piglets are exposed to, providing conditions that allow for optimum piglet growth and development. An influx of publications within this area has occurred in recent times and with this, interest surrounding its application in pork production has increased. However, it can be difficult to distinguish which research is of most relevance to industry in terms of delivering repeatable and reliable production outcomes. In this review, we describe the literature surrounding research within pigs, predominantly during the preweaning period that has either provided solutions to industry problems or is generating information targeted at addressing relevant industry issues, with the focus being on studies demonstrating causation where possible. This review will provide a basis for the development of new studies targeted at understanding how to better support initial intestinal microbiota colonisation in order to improve piglet health and survival.

Use of bioelectrical impedance spectroscopy to provide a measure of body composition in sows.

The ability to accurately estimate fat mass and fat-free mass (FFM) has the potential to improve the way in which sow body condition can be managed in a breeding herd. Bioelectrical impedance spectroscopy (BIS) has been evaluated as a practical technique for assessment of body composition in several livestock species, but similar work is lacking in sows. Bioelectrical impedance uses population-specific algorithms that require values for the apparent resistivities of body fluids and body proportion factors. This study comprised three major aims: (i) to derive apparent resistivity coefficients for extracellular water (ECW) and intracellular water (ICW) required for validation of BIS predictions of total body water (TBW) in live sows against standard reference tracer dilution methods; (ii) to develop predictions of TBW to body composition prediction algorithms, namely FFM, by developing a body geometry correction factor (Kb) and (iii) to compare the BIS predictions of FFM against existing impedance predictors and published prediction equations for use in sows, based on physical measurements of back-fat depth and BW (P2-based predictors). Whole body impedance measurements and the determination of TBW by deuterium dilution and ECW by bromide dilution were performed on 40 Large White x Landrace sows. Mean apparent resistivity coefficients of body fluids were 431.1 Ω.cm for ECW and 1827.8 Ω.cm for ICW. Using these coefficients, TBW and ECW were over-estimated by 6.5 and 3.3%, respectively, compared to measured reference values, although these differences were not statistically different (P > 0.05). Mean Kb was 1.09 ±â€¯0.14. Fat-free mass predictions were 194.9 kg, which equates to 60.9% of total sow weight, and 183.0 kg for BIS and the deuterium dilution method, respectively. Mean differences between the predicted and measured FFM values ranged from -8.2 to 32.7%, but were not statistically different (P > 0.05). Method validation (leave-one-out procedure) revealed that mean differences between predicted and measured values were not statistically significant (P > 0.05). Of the impedance-based predictors, equivalence testing revealed that BIS displayed the lowest test bias of 11.9 kg (8.2%), although the P2-based prediction equations exhibited the lowest bias and percentage equivalence, with narrow limits of agreement. Results indicate although differences between mean predicted and measured values were not significantly different, relatively wide limits of agreement suggest BIS as an impractical option for assessing body composition in individual sows compared to the use of existing prediction equations based on BW and back fat.

Reduced growth performance in gilt progeny is not improved by segregation from sow progeny in the grower-finisher phase.

Gilt progeny (GP) are born and weaned lighter than sow progeny (SP) and tend to have higher rates of mortality and morbidity. This study quantified the lifetime growth performance differences between GP and SP and, additionally, evaluated whether segregating GP and SP in the grower-finisher period compared to mixing them within common pens reduced this variation. It was hypothesised that GP would be lighter than SP at every stage and segregation would improve growth performance of both GP and SP. All piglets born to 61 gilts (parity 1) and 47 sows (parities 2 to 7; mean 3.5 ± 0.2) were allocated to four treatments at 10 weeks of age: (i) GP housed together (GG), (ii) GP mixed (M) with SP (GM), (iii) SP housed together (SS) and (iv) SP mixed with GP (SM). The GM and SM pigs were housed together in common pens after movement into the grower-finisher facility. Individual live weight of all progeny was recorded at birth, weaning (WWT), 10 weeks of age (10WT) and sale (SWT). Individual hot carcass weight (HCW), fat depth at the head of the last rib (P2) and dressing percentage were measured at slaughter. Gilt progeny were lighter at birth (P = 0.038), weaning (P < 0.001) and through to sale (P = 0.001) than SP. Nursery and grower-finisher performance differences in GP were highly attributable to their lower WWT compared to SP (P < 0.001 when fitted as a covariate). Segregation of GP and SP increased grower-finisher average daily gain (ADG) in SP but decreased ADG and SWT in GP (P < 0.10). Segregated SP had increased average daily feed intake but only in males (P = 0.007); HCW (P < 0.001) and P2 fat depth (P = 0.055) were higher in mixed female GP, but there was no difference (P > 0.10) in female SP, or in males. In conclusion, GP were lighter at every stage than SP and differences after weaning were highly related to the lighter WWT of GP. Under the conditions of this study, overall segregation of GP and SP showed no consistent advantages in growth performance for both groups and differed significantly between males and females.

Poorer lifetime growth performance of gilt progeny compared with sow progeny is largely due to weight differences at birth and reduced growth in the preweaning period, and is not improved by progeny segregation after weaning.

Gilt progeny (GP) are born and weaned lighter than sow progeny (SP) and have higher rates of mortality. This study aimed to quantify the performance and survival differences between GP and SP throughout the entire production cycle from birth to sale. Furthermore, the study looked at the effects of segregating GP and SP compared with commingling during rearing within common pens. It was hypothesized that GP would be lighter than SP at every age and have lower rates of survival accompanied by higher rates of medication, and that segregating GP and SP would improve the growth and survival of both groups. All progeny born to 109 gilts (parity 1) and 94 sows (parities 2 to 8) were allocated to 4 postweaning treatments at birth: GP separately penned, GP mixed with SP in a common pen (GM), SP separately penned, and SP mixed with GP in a common pen (SM), with littermates split among treatments. The GM and SM pigs were penned together after weaning. Individual live weight of all progeny was recorded at birth (birth weight [BWT]), weaning (28 d; weaning weight [WWT]), 10 wk of age (10-wk weight [10WT]), and sale (22-23 wk; sale weight [SWT]). Individual HCW, backfat depth, loin depth, and dressing percentage were measured at slaughter. All postweaning mortalities and medications were recorded. The GP had a lighter BWT ( = 0.032), WWT ( < 0.001), 10WT ( < 0.001), and SWT ( < 0.001) than SP as well as a lower HCW ( < 0.001) and dressing percentage ( = 0.012). Postweaning performance differences were mostly attributable to the lighter WWT of GP compared with that of SP when WWT was fitted as a covariate. The GP had a higher mortality in the immediate postweaning period (weaning to 10 wk of age; = 0.028) and from weaning to sale ( = 0.012) than SP, which was also attributable to lower WWT. The GP exhibited a higher incidence of mortality ( = 0.011) due to respiratory tract infection in the grower-finisher period, despite similar medication rates ( = 0.83). Segregation of GP and SP between pens presented no benefit in terms of growth and survival of both groups while requiring added labor and production considerations and, therefore, is not recommended. This study confirms that GP are lighter than SP, on average, at every stage of life from birth to slaughter and that their performance before weaning is an important determinant for whole-of-life performance.

Supra-nutritional vitamin E supplementation for 28 days before slaughter maximises muscle vitamin E concentration in finisher pigs.

A 4 × 3 factorial experiment (n=8 pigs per treatment combination) was conducted with 96 female Landrace × Large White pigs to examine the required level of dietary vitamin E and optimum feeding duration before slaughter to maximise muscle vitamin E content in the Longissimus thoracis et lumborum (LTL) muscle. The respective factors were four dietary levels of vitamin E (supplemented as dl-α-tocopheryl acetate; 35, 300, 500, and 700 IU/kg) and three feeding durations (14, 28 and 42 days before slaughter). Vitamin E concentration in the LTL was maximised at 6 mg/kg, which was achieved by feeding a 700 IU vitamin E diet for 28 days before slaughter (P<0.001). There was no further increase in the vitamin E content of the LTL by feeding the high vitamin E diet more than 28 days before slaughter.

Vitamin E and omega-3 fatty acids independently attenuate plasma concentrations of proinflammatory cytokines and prostaglandin E3 in Escherichia coli lipopolysaccharide-challenged growing-finishing pigs.

This study tested the hypothesis that vitamin E (Vit E) and omega-3 fatty acids will additively attenuate the production of proinflammatory cytokines and PGE2 in immune system­stimulated growing­finishing pigs. A total of 80 mixed sex pigs weighing 50.7 ± 0.76 kg (mean ± SE) were blocked and stratified based on sex and BW to a 2 × 2 factorial design with the respective factors being 1) without and with 300 IU Vit E and 2) without and with 25% replacement of tallow to linseed oil as a source of n-3 fatty acids. Each treatment consisted of 4 replicate pens with 5 pigs (3 barrows and 2 gilts) per pen. All pigs were challenged with an intramuscular injection of Escherichia coli lipopolysaccharide (LPS; O111:B4) twice weekly over the 6-wk experiment. After LPS challenge, pigs fed a diet supplemented with n-3 fatty acids had fewer (P < 0.05) white blood cells and tended to show both a reduced (P < 0.10) proportion of lymphocytes and IgG concentration compared with pigs fed a diet without any supplements. Supplementation of n-3 fatty acids reduced (P < 0.01 and P < 0.05) serum concentrations of cortisol and tumor necrosis factor α (TNF-α), respectively. The serum concentration of PGE2 was decreased (P < 0.05) with supplementation of both Vit E and n-3 fatty acids; however, the extent of the reduction was greater (P < 0.001) in pigs fed an n-3 fatty acid­supplemented diet. However, there were no additive effects of the combined supplementation of Vit E and n-3 fatty acids on serum concentrations of proinflammatory cytokines and PGE2. The results suggest that n-3 fatty acids independently attenuate production of TNF-α and PGE2 in immune system­stimulated growing­finishing pigs.

Does the environmental background (intensive v. outdoor systems) influence the behaviour of piglets at weaning?

Under intensive pig husbandry, outdoor systems offer a more complex physical and social environment compared with indoor systems (farrowing sheds). As the rearing environment affects behavioural development, it can, therefore, influence behavioural responses of pigs to stressful environments in later stages of production. We tested how the rearing environment influenced behavioural responses to a novel arena test in piglets on the day that they were weaned and mixed into large groups. We recorded video footage and compared the behavioural responses of 30 outdoor-raised and 30 farrowing shed-raised piglets tested in an experimental arena and sequentially exposed to four challenges (each for 5 min) on the day of weaning. Quantitative and qualitative behavioural measures were recorded using time budgets and scoring demeanour or 'qualitative behavioural expression' (using Qualitative Behavioural Assessment (QBA)). When held in isolation (challenge 1), both groups were scored as more 'scared/worried', while outdoor-raised piglets spent more time eating and jumping against the arena walls. Both groups interacted with a plastic ball (challenge 2: exposure to a novel object) during which they were scored as more 'playful/curious' than other challenges. When a food bowl was introduced (challenge 3), farrowing shed-raised piglets were more interested in playing with the food bowl itself, whereas outdoor-raised piglets spent more time eating the feed. Finally, there were no significant differences in social behaviour (challenge 4: introduction of another piglet) between the two groups in terms of the latency to contact each other, amount of time recorded engaged in aggressive/non-aggressive social interactions or QBA scores. Although piglets spent 30% of their time interacting with the other piglet, and half of this time (47%) was engaged in negative interactions (pushing, biting), the levels of aggression were not different between the two groups. Overall, outdoor-raised piglets ate more and were scored as more 'calm/passive', whereas farrowing shed-raised piglets spent more time investigating their environment and were scored as more 'playful/inquisitive'. In conclusion, we did not find differences in behaviour between outdoor-raised and farrowing shed-raised piglets that would highlight welfare issues. The differences found in this study may reflect conflicting affective states, with responses to confinement, neophobia and motivation for exploration evident.

Neonatal oxytocin administration and supplemental milk ameliorate the weaning transition and alter hormonal expression in the gastrointestinal tract in pigs.

The aim of this study was to investigate the influences of milk supplementation during lactation, over 1 wk after weaning, and oxytocin administration for the first 14 d of life on the pigs' response to weaning. Pigs from 20 litters were allocated to each of these 3 treatments in a randomized factorial design. Oxytocin was administered subcutaneously daily from 0 to 14 d of age at a rate of 10 I.U. per kg. The milk supplement consisted of a mixture of 25% skim milk powder offered either during lactation between 10 and 20 d of age or for the first week after weaning as a transitional diet along with dry pellets. Pigs were weaned at 21 d of age. Growth rate was measured from birth to slaughter at 140 d of age and feed intake of supplemental milk or feed from 10 to 56 d of age. Organ weights (heart, liver, stomach, and kidneys) and the gene expression of ghrelin, leptin, and glucagon-like peptides (glucagon-like peptide-1 and glucagon-like peptide-2) were measured in the stomach, ileum, and duodenum at 10, 21, and 28 d of age. Milk supplementation after weaning resulted in immediate feed intake and partially alleviated the depression in growth rate over the first 7 d postweaning (P < 0.001), but milk supplementation during lactation had no effects (P > 0.1). However, effects were only transient and disappeared once the milk liquid diet was removed. Neonatal oxytocin administration reduced weight loss over the first 2 d after weaning (P = 0.03), without affecting feed intake (P > 0.1), hence possibly reducing weaning stress. Seven days after weaning, oxytocin-treated pigs had greater stomach ghrelin and leptin expression (both P = 0.02), and pigs supplemented with milk after weaning had greater stomach leptin and glucagon-like peptide-2 expression (P = 0.02 and P = 0.05, respectively). Hence, neonatal oxytocin administration or postweaning milk supplementation are both effective means of enhancing gastric leptin expression and reducing weight loss at weaning, likely improving gut health during this critical period.

Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post-weaning diarrhoea without using in-feed antimicrobial compounds.

For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic-resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post-weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level.

Prediction of apparent, standardized, and true ileal digestible total and reactive lysine contents in heat-damaged soybean meal samples.

Forty-two individually housed entire male pigs weighing 37.5 ± 0.15 kg (mean ± SEM) were used in a randomized block design having 7 dietary treatments (n = 6). The dietary treatments were 5 semisynthetic diets containing 350 g/kg of soybean (Glycine max) meal (SBM) with variable heat treatments (0, 7, 14, 21, and 28 min autoclaved at 135°C), a protein free (N-free) diet, and an enzymatically hydrolyzed casein (EHC) diet. Heat treatment linearly decreased (P < 0.001) total Lys content from 27.5 to 19.2 g/kg and reactive Lys content from 23.4 to 11.7 g/kg. Apparent, standardized, and true ileal digestible total and reactive Lys contents linearly decreased (P < 0.001) with increasing severity of heat treatment and were accurately predictable (P < 0.001) from total and reactive Lys content in heat-damaged SBM. These data indicate that excessive heat processing of SBM reduced both the content (P < 0.001) and digestibility (P < 0.001) of total and reactive Lys in SBM.

An increased ratio of dietary tryptophan to lysine improves feed efficiency and elevates plasma tryptophan and kynurenine in the absence of antimicrobials and regardless of infection with enterotoxigenic Escherichia coli in weaned pigs.

This experiment examined if a higher ratio of dietary Trp:Lys in the absence of antimicrobials improves production indices and modulates diarrhea in weaned pigs infected with enterotoxigenic Escherichia coli (ETEC). Effects of the Trp:Lys ratio on plasma levels of Trp and its metabolite kynurenine (Kyn) were also examined. Individually housed mixed-sex pigs (n = 72) weaned at 21 d of age (Landrace × Large White; initial BW of 6.3 ± 0.32 kg) were stratified into 1 of 6 treatments (n = 12) according to a 2 × 3 factorial arrangement of (i) infection or without infection with ETEC and (ii) 3 dietary standardized ileal digestible (SID) Trp:Lys ratios of 0.17, 0.21, or 0.26 in a randomized complete block design. Pigs were fed diets (10.4 MJ NE; 1.24% SID Lys; 19.5% CP) ad libitum for 3 wk after weaning. Pigs were infected with ETEC (O149:K98:K88) at 72, 96, and 120 h after weaning and then bled on day 11. A Trp:Lys ratio of 0.26 improved (P = 0.021) G:F over the study period compared to other ratios, without an infection effect (P > 0.05). Treatments did not affect ADG or ADFI (P > 0.05). Infection increased (P = 0.039) the diarrhea index and increased fecal consistency scores (P = 0.010). Plasma Trp and Kyn were lower (P < 0.001) in pigs fed 0.17 Trp:Lys than those fed ratios of 0.21 and 0.26 and were not affected (P > 0.05) by infection. In conclusion, in the absence of antimicrobials, increasing the dietary Trp:Lys ratio to 0.26 improved G:F after weaning and increased plasma levels of Trp and Kyn.

Whole body protein deposition and plasma amino acid profiles in growing and/or finishing pigs fed increasing levels of sulfur amino acids with and without Escherichia coli lipopolysaccharide challenge.

A split plot experiment with 72 male pigs weighing 52.9 ± 0.39 kg (mean ± SEM) was conducted to examine AA partitioning and body protein deposition (PD) in response to increasing dietary sulfur amino acids (SAA) with or without immune system (IS) activation. The main plot was with and without IS activation, and 4 diets containing different amounts of standardized ileal digestible (SID) SAA (SAA to Lys ratios of 0.45, 0.55, 0.65 and 0.75) were the subplots. Activation of IS was achieved by intramuscular injection of Escherichia coli lipopolysaccharides (LPS; serotype 055:B5, Sigma; 30 µg/kg BW) every Monday and Thursday, with control pigs injected with sterile saline. Maximum body PD, measured by dual-energy X-ray absorptiometry (DXA), and minimum plasma urea content were achieved at SID SAA:Lys ratio of 0.55 in saline-injected pigs but were achieved at a SID SAA:Lys ratio of 0.75 in IS-activated pigs. Immune system activation increased rectal temperature (P < 0.05), plasma haptoglobin (1.1 vs. 2.0 mg/mL; P < 0.001), and the proportion of neutrophils (0.39 vs. 0.42; P < 0.05) and decreased serum albumin content (38.4 vs. 36.8 g/L; P < 0.01). Increasing dietary SAA had no effects on these variables. Immune system-activated pigs had lower levels of homocysteine (Hcy; P < 0.001) and a lower Ser content (P < 0.05). Results showed that increasing dietary SAA as DL-methionine in growing and/or finishing pigs altered plasma AA contents, and that use efficiency of the AA was improved when greater levels of SAA were supplemented in IS-activated pigs.

Reducing the length of time between slaughter and the secondary gonadotropin-releasing factor immunization improves growth performance and clears boar taint compounds in male finishing pigs.

The objective of this study was to evaluate whether altering the timing of the secondary anti-gonadotropin-releasing factor (GnRF) immunization closer to slaughter in male finishing pigs would reduce the increase in P2 fat depth (6.5 cm from the midline over the last rib), while still limiting the incidence of boar taint. Entire male pigs are immunized against GnRF to reduce the concentration of testicular steroids that in turn limits the incidence of boar taint. Additionally, testicle measurements and color measurements were taken to examine whether they could be used to differentiate nonimmunized entire males from immunized male pigs. A total of 175 Large White × Landrace entire male pigs aged 16 wk (59 kg of BW) were used in a completely randomized design with 5 treatment groups based on the time that pigs received the secondary immunization before slaughter. Pigs were housed in groups of 7 and randomly allocated to 1 of 5 treatments with 5 replicates per treatment. The treatment groups were as follows: no secondary immunization before slaughter, and the secondary immunization given at 2, 3, 4, or 6 wk before slaughter. The P2 fat depth levels were reduced (P = 0.054) with the secondary immunization closer to slaughter (11.7, 11.3, 12.8, 12.6, and 13.7 mm for no secondary immunization, secondary immunization at 2, 3, 4, and 6 wk before slaughter, respectively). Androstenone concentration did not exceed the generally accepted industry sensory threshold of 1.0 µg/g of fat, and both androstenone concentration in the adipose tissue and testosterone concentrations in the blood were suppressed (P < 0.001) in all immunized pigs regardless of timing of the secondary immunization compared with pigs that did not receive the secondary immunization. Skatole concentration of all pigs in the experiment did not exceed the generally accepted industry sensory threshold of 0.2 µg/g. Testes weight was reduced (P < 0.001) with increased time between slaughter and the secondary immunization. Immunized pigs, regardless of time before slaughter, had greater L* (lightness) and b* (yellowness) color of the testicle surface (P < 0.001 and P = 0.020, respectively), and less a* (redness) color compared with entire males (P < 0.001). The study provides further evidence of the efficacy of the anti-GnRF immunization and indicates that the secondary immunization can be moved closer to slaughter, while still limiting the incidence of boar taint. Testicle measurements and color measurements together could provide a method of discrimination between carcasses from immunized entire males clear of boar taint and tainted carcasses.

Diets containing inulin but not lupins help to prevent swine dysentery in experimentally challenged pigs.

Swine dysentery is a contagious mucohemorrhagic diarrheal disease caused by the intestinal spirochete Brachyspira hyodysenteriae that colonizes and induces inflammation of the cecum and colon. It has been reported that a diet containing chicory root and sweet lupin can prevent swine dysentery. This experiment was conducted to test the hypothesis that inulin in the chicory root rather than galactans in lupins was responsible for protective effects. An experiment with a 2 × 2 factorial arrangement of treatments was undertaken using pigs fed barley- and triticale-based diets, with the main effects being protein source [185 g/kg of canola meal (decreased galactans) or 220 g/kg of lupins (greater galactans)] and inulin supplementation (0 or 80 g/kg). Forty Large White × Landrace pigs weighing 21 ± 3 kg, with 10 pigs per diet, were allowed to adapt to the diets for 2 wk, and then each pig was challenged orally 4 times with a broth culture containing B. hyodysenteriae on consecutive days. Pigs were killed when they showed clinical signs of dysentery or 6 wk postchallenge. Pigs fed diets without inulin had 8.3 times greater risk (P = 0.017) of developing swine dysentery and were 16 times more likely (P = 0.004) to have colon contents that were culture-positive for B. hyodysenteriae, compared with the pigs fed a diet with 80 g/kg of inulin. Diets containing lupins did not prevent pigs from developing clinical swine dysentery; however, inclusion of lupins or inulin or both in the diets delayed the onset of disease compared with the diet based mainly on canola meal (P < 0.05). Diet did not influence the total concentration of organic acids in the ileum, cecum, or upper and lower colon; however, the molar proportions of the organic acids were influenced (P < 0.05). Consequently the pH values in the cecum, and upper and lower colon were not influenced (P > 0.05) by diet. However the pH values of the ileal digesta were decreased in pigs fed the diet with both lupins and inulin compared with the diet containing only lupins (P < 0.05). In conclusion, this study shows that diets supplemented with highly fermentable carbohydrates from inulin protected pigs against developing swine dysentery.

Feeding a diet with decreased protein content reduces indices of protein fermentation and the incidence of postweaning diarrhea in weaned pigs challenged with an enterotoxigenic strain of Escherichia coli.

This study evaluated the effect of feeding low protein (LP) diets for 7 or 14 d after weaning or a high protein (HP) diet for 14 d after weaning on postweaning diarrhea (PWD), indices of protein fermentation, and production in pigs infected or not infected per os with an enterotoxigenic strain of Escherichia coli. A total of 72 female pigs weaned at aged 21 d with initial BW of 5.9 +/- 0.12 kg were used in a 3 x 2 factorial arrangement of treatments. The factors were 3 feeding regimens associated with different combinations of feeding duration and diet CP level: (i) HP diet (256 g of CP/kg) fed for 14 d after weaning, (ii) LP diet (175 g of CP/kg) fed for 7 d after weaning, and (iii) LP diet fed for 14 d after weaning; and infection or noninfection with an enterotoxigenic strain of E. coli (10(7) cfu/mL, serotype O149:K91:K88) at 72, 96, and 120 h after weaning. The LP diets were fortified with crystalline Ile and Val to achieve an ideal AA pattern. A second-stage diet (213 g of CP/kg) was fed to pigs at the conclusion of each feeding regimen, and the study finished 4 wk after weaning. None of the diets contained antimicrobials. Feeding the LP diets decreased (P < 0.001) plasma urea nitrogen, fecal ammonia nitrogen concentrations, and the incidence of PWD, but increased (P = 0.001) fecal DM content compared with pigs fed HP in the 2-wk period after weaning. Infection increased shedding of beta-hemolytic E. coli (P < 0.001), the incidence of PWD (P < 0.001), and fecal ammonia nitrogen concentrations (P < 0.01), but did not interact with feeding regimen, after weaning. Pigs challenged with E. coli grew more slowly (P < 0.001) and had decreased G:F (P < 0.01) compared with nonchallenged pigs in the 4-wk period after weaning. Feeding an LP diet for 7 or 14 d after weaning markedly reduced the incidence of PWD after infection with beta-hemolytic E. coli. Infection was associated with decreased indices of protein fermentation in the distal gastrointestinal tract but did not compromise the growth of weaner pigs in the 4-wk period after weaning.

Variation in digestible energy content of Australian sweet lupins (Lupinus angustifolius L.) and the development of prediction equations for its estimation.

Sixty-three male pigs (Landrace x Large White) weighing 49.5 +/- 0.40 kg were used to (1) examine the variation in DE content of Lupinus angustifolius L. in relation to variety and geographical growing region and (2) establish prediction equations for DE content from physical and chemical composition. The pigs were randomly allocated to a 4 x 2 factorial treatment design with respective factors being 4 varieties (cv. Belara, Coromup, Mandelup, and Tanjil) and 2 growing locations (northern and southern agricultural areas of Western Australia). In addition, a wheat control diet was fed as a reference for calculation of lupin DE content. The lupins were ground through a hammer mill fitted with a 4-mm screen to a mean particle size of 888 mum. Pigs were fed their respective experimental diets at 3 times maintenance energy level [3 x (0.458 x BW(0.75))/diet DE] in the study. The DE content of lupins ranged from 13.3 to 15.7 MJ/kg with a mean value of 14.2 MJ/kg. Variety of lupins affected (P < 0.01) the DE content, and lupins grown in the northern agricultural region had a greater DE content than the same lupins grown in the southern agricultural area (P < 0.01). Although the variation in DE content of lupins was mostly caused by significantly greater DE content of cv. Coromup grown in the northern agricultural region, the results suggest that genetic and environmental conditions during the growth of lupins have a significant impact on the utilization of energy in grower pigs. Simple regression analysis showed that prediction of DE content was possible from the proportion of hulls [R(2) = 0.88, residual SD (RSD) = 1.116, P < 0.001], 1,000-seed weight (R(2) = 0.77, RSD = 1.092, P < 0.01), and soluble arabinoxylan content (R(2) = 0.64, RSD = 1.072, P < 0.05). Multiple regression analysis showed that adding total nonstarch polysaccharide (R(2) = 0.96, RSD = 1.187, P < 0.01) and soluble nonstarch polysaccharide (R(2) = 0.95, RSD = 1.200, P < 0.01) to the equation along with the proportion of hull and 1,000-seed weight significantly improved the accuracy of prediction. Results indicate that the DE content of lupins varies by up to 2.4 MJ/kg and that the DE content can be predicted with a good degree of accuracy using physical and chemical characteristics.

Levels of copper and zinc in diets for growing and finishing pigs can be reduced without detrimental effects on production and mineral status.

One hundred and sixty pigs were used to evaluate dietary copper (Cu) and zinc (Zn) supplementation on performance, fecal mineral levels, body mineral status and carcass and meat quality. Diets differed in mineral form (MF) (Cu and Zn in the form of proteinate amino acid chelate (organic) or sulfate (inorganic)) and inclusion level (IL) (27 mg/kg of total Cu and 65 mg/kg of total Zn ('low') or 156 mg/kg of total Cu and 170 mg/kg of total Zn ('high')) according to a 2 × 2 factorial arrangement of treatments. Pigs were used from 25 to 107 kg body weight (BW) and fed their respective diets ad libitum. Blood and fecal samples were collected on days 14 and 77 of the experiment. Blood was analyzed for concentration of Cu and Zn, hemoglobin (Hb), Cu content of red blood cells (RBC Cu) and alkaline phosphatase (ALP) and feces for Cu and Zn concentration. Hot carcass weight (HCW) and backfat depth were measured at slaughter and indices of meat quality were assessed on a section of longissimus thoracis. Liver, kidney and bone samples were collected immediately after slaughter and liver and kidney were tested for Cu and Zn content, while bone was only tested for Zn. Over the entire experimental period (25 to 107 kg BW) no significant treatment differences in average daily gain (ADG) or average daily feed intake (ADFI) occurred; however, feed conversion ratio (FCR) was improved by the inclusion of proteinate amino acid chelate (P = 0.012). Copper and Zn concentrations in feces were in direct proportion to the IL in the diet. Blood mineral levels were within normal physiological ranges in all treatments and tissue Cu and Zn concentrations increased with dietary IL (P < 0.05). Results indicate that Cu and Zn fecal concentrations were reduced by approximately 6-fold for Cu and by 2.5-fold for Zn by feeding 27 mg/kg Cu and 65 mg/kg Zn, in either the proteinate amino acid chelate or the sulfate form, compared with a diet containing 156 mg/kg Cu and 170 mg/kg Zn. This decrease in total dietary Cu and Zn did not reduce performance or mineral status of pigs.