Boar taint, meat quality and fail rate in entire male pigs and male pigs immunized against gonadotrophin releasing factor as related to body weight and feeding regime

Comparison of the meat quality and fatty acid profile of muscles in finishing Xiangcun Black pigs fed varied dietary energy levels

To study the effects of dietary energy level on the meat quality of different muscles in finishing pigs, 400 Xiangcun Black pigs (BW = 79.55 ± 4.77 kg) were randomly assigned to 5 treatments with varied calculated digestive energy (DE) at 3,050, 3,100, 3,150, 3,200 and 3,250 kcal/kg, respectively. Each treatment had 8 replicates with 10 pigs per replicate. Meat quality, amino acid and fatty acid composition were tested in this study. No differences in average daily gain, average daily feed intake or feed-to-gain ratio (P > 0.05) were observed among dietary treatments. Glycogen concentrations of longissimus dorsi (LD) muscle in DE3150 was higher than those in other groups (P < 0.05). The crude fat concentration of biceps femoris (BF) muscle in DE3250 tended to be higher than that in DE3150 and DE3100 groups (P < 0.05). Pigs in DE3250 and DE3200 had higher fiber density and smaller cross-sectional area of BF muscle than those in DE3150 (P < 0.05). Pigs in DE3150 had the highest Cu concentration in LD muscle compared with those in DE3200, DE3250 (P < 0.05). The C16:1 proportion of LD muscle was lower (P < 0.01) and C20:1 was higher (P < 0.05) in DE3050 than that in the other dietary treatments. The C18:3n6 and C20:3n6 proportions of BF muscle in DE3150 were higher than those in DE 3050, DE3200 and DE3250 (P < 0.05). For LD muscle, mRNA expressions of type I and IIa MyHC in group DE3150 were higher than other treatments (P < 0.01). The LD muscle in DE3150 expressed higher PPARd than in other groups (P < 0.01). Pigs in DE3100 expressed higher FOX1 than in DE3200 and DE3250 (P < 0.05). Sterol-regulatory element binding proteins (SREBPa) mRNA expression decreased linearly when dietary energy level increased in BF muscle (P < 0.01). In conclusion, a 200 kcal/kg decrease in digestible energy for 4 consecutive weeks did not affect growth performance of Xiangcun Black pigs. Furthermore, LD and BF muscle respond differently to dietary energy level, and meat quality was improved by the medium energy level during the finishing phase.

Locally Grown Crops and Immunocastration in Fattening Heavy Pigs: Effects on Performance and Welfare

This study aimed to explore dietary replacement soybean meal (SBM) with local pea seeds (PS-L) and the effects of surgically castrated (CM) or immunocastration (IM) in heavy male pigs, on growth performance, feeding behaviour, and tail and ear lesions. Four treatments were arranged factorially (2 × 2), with two sexes and two dietary treatments (96 pigs in eight pens). The inclusion of PS-L was 25%, 30%, and 40% during three phases (40−80 kg, 80−110 kg, and 110−140 kg, respectively). No difference in average daily feed intake (ADFI) and body-weight (BW) between PS-L and SBM could be demonstrated (p > 0.05), but PS-L diet decreased the average daily gain (ADG) at 110−140 kg of BW (p < 0.001) and increased feed conversion rate (FCR) (p < 0.05). The ADG was higher (p < 0.01) in IM than CM in all fattening periods, and the FCR in IM was lower (p < 0.05) than in barrows. IM pigs had lower dressing percentage than CM (p < 0.01). Pigs fed a PS-L diet ate faster but increased their passive behaviour compared with those fed SBM. In conclusion, the PS-L diet did not reduce BW and improved passive behaviour, and IM grew more efficiently, regardless of diet.

Immunocastration with gene vaccine (KISS1) induces a cell-mediated immune response in ram testis: A transcriptome evaluation

Immunocastration vaccines achieve their effects through neutralization of the endogenous hormone by the humoral antibody produced against the immunized genes. But there is little information regarding cell-mediated immune response on the gonadal function of the immunized model is available. In this study, we used ram as a model animal to identify the cellular immune response in testicular tissues of rams immunized with intranasal KISS1 gene vaccine. The immune castration model was evaluated by sexual behaviors, spermatogenesis, and serum hormone profiles after the KISS1 gene immunization. Transcriptome analysis of testicular tissues was carried out to identify the expressions of protein-coding genes involved in cellular immunity. The results showed that we successfully constructed the KISS1 immune castration ram model, in which testicular growth and development, testosterone and kisspeptin-54 levels, and sexual function were suppressed in immunized rams (P <0.05). Using HiseqTM 2000 high sequencing for ram testicular, we identified 21 differentially expressed genes (DEGs) related to cellular immunity, of which, 14 genes were up-regulated and seven genes were down-regulated in the testis of the immunized group (P<0.05). The Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that these differentially expressed genes were enriched in the antigen presentation process mediated by MHC class I and the cytotoxic pathway mediated by natural killer cells. It is concluded that KISS1 gene vaccine induced the cell-mediated immune response in testicular tissue to suppress reproductive activities in rams.

Gender effects on pork quality and calpain-1 and calpastatin gene expression in male pig muscle

Studies that investigate the expression of genes related to the tenderness of meat from entire and immunocastrated male pigs have not yet been performed. The objective of this study was to investigate the association between gender (entire male and immunocastrated) and the meat quality of pigs, as well as to quantify the expression of calpain-1 and the calpastatin gene. Regarding carcass measurements and meat quality, boars presented lower values of muscle depth (P = 0.028), subcutaneous fat thickness (P = 0.046), L* value (P = 0.004) and cook loss (P = 0.008) than the immunocastrated pigs. The boars presented greater calpain-1 gene expression (P = 0.006) and lower calpastatin gene expression (P = 0.003) than immunocastrated pigs. This study shows that combined with other factors the gene expression can contribute to a tender meat from boars due to their higher calpain-1 expression and lower calpastatin expression than those of immunocastrated male pigs.

The Use of Pork from Entire Male and Immunocastrated Pigs for Meat Products-An Overview with Recommendations

Due to the strong public initiative in Europe and increased regulator focus to mitigate pain, surgical castration of pigs is being gradually abandoned, while the importance of other sex categories like entire males (EM) and immunocastrates (IC) increases. Although beneficial for animal welfare and economics, their use also brings forward several quality problems. Besides the occurrence of boar taint in EM, these include excessive carcass leanness, softer fat, meat color and pH deviations, inferior water holding capacity and increased meat toughness. In this paper, the raw material differences between the male sex categories and their influence on product quality are reviewed, and possible solutions are presented. Using EM for dried or thermally processed products may result in lower processing yields and inferior sensory quality, which may partially be prevented by applying specific processing adaptations. Immunocastration is a viable solution, especially when prolonging the vaccination to slaughter interval. Low to medium levels of boar taint can be effectively managed in most of the meat products, applying procedures like cooking, microbial inoculation or masking (by spices and especially smoking), while highly tainted material can be valorized only by combining various methods and/or with dilution of the tainted meat.

Immuno-castration of female and male pigs with anti-gonadotrophin releasing hormone vaccine: Morphometric, histopathological and functional studies of the reproductive system

Immuno-castration is increasingly recommended in pigs due to welfare reasons; however, there are few studies in females compared to males. This aim of this study was to investigate the effects of immuno-castration in female and male pigs. The weight, the morphometric and microscopic characteristics of the reproductive organs, and the hormone concentrations were studied in 12 immunocastrated females (IF) and 12 immunocastrated males (IM) and compared with control animals (C). At slaughter, IF tended to have greater body weights than CF (P =  0.051), whereas in IM and CM pigs there were not body weight differences (P =  0.140). The weight of the reproductive tract and size of all individual organs were less in IF compared with CF. Results from histological assessments indicated IF had more atretic follicles and a thinner endometrial mucosa than control females. Hormone concentrations were not different between CF and IF (P >  0.050). As a result of immuno-castration, there was impaired spermatogenesis in most males. Results from microscopic evaluations indicated there was a marked decrease of spermatogonial cells and size of Leydig cells in the testicles. Accessory gland structures were affected in CM and IM with there being differences in gross and microscopic characteristics. Testosterone concentrations, unlike estradiol, were different in IM compared to CM (P <  0.001). These results provide evidence that immuno-castration with the anti-gonadotrophin releasing hormone vaccine is effective in female and male pigs and induces morphological and endocrine changes incompatible with fertility.

Electrical stimulation or moisture infusion improves the eating quality attributes of loin and silverside cuts from female and immunocastrated male pigs

This study validated the effect of gender (female, immunocastrated male; n = 50), electrical stimulation (none or 150 mA constant current for 30 s at 2 min post-slaughter) and ageing period (2 or 14 d) on the eating quality of pork roast and stir fry sourced from the loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) and steak from the loin only. Moisture infusion was applied to 2 d aged, non-stimulated primals as a positive control treatment. Neither gender nor ageing period influenced (P > 0.05) eating quality. Electrical stimulation and moisture infusion were each effective interventions in improving pork eating quality, but their effects were inconsistent between the five cuts evaluated. No interventions achieved the fail rate target of <10% for quality grade for all cuts, indicating that additional interventions are needed to enable industry to consistently deliver high quality pork.

Guaranteeing the quality and integrity of pork - An Australian case study

The Australian pork industry is strongly committed to assuring the integrity of its product, with substantial research investment made over the past ten years to develop and implement systems to assure the consistency and quality of fresh pork and to enable accurate tracing of unpackaged fresh pork back to property of origin using trace elemental profiling. These initiatives are pivotal to allow Australian pork of guaranteed eating quality to be successfully positioned as higher value products, across a range of international and domestic markets, whilst managing any threats of product substitution. This paper describes the current status of the development of a predictive eating quality model for Australian pork, utilizing eating quality datasets generated from recent Australian studies. The implementation of trace elemental profiling, by Physi-Trace™, to verify and defend provenance claims and support the supply of consistently high eating quality Australian pork to its customers, is also discussed.

Reversibility and safety of KISS1 metastasis suppressor gene vaccine in immunocastration of ram lambs

Objective

The aim of this study was to investigate the reversibility and safety of KISS1 metastasis suppressor (KISS1) gene vaccine in immunocastration.

Methods

Six eight-week old ram lambs were randomly divided into vaccinated and control groups. The vaccine (1 mg/ram lamb) was injected at weeks 0, 3, and 6 of the study. Blood samples were collected from the jugular vein before primary immunization and at weeks 2, 4, 6, 10, 14, 22, and 30 after primary immunization. All ram lambs were slaughtered at 38 weeks of age, and samples were collected.

Results

The specific anti-KISS1 antibody titers in vaccinated animals were significantly higher and the serum testosterone level was significantly lower than those in the control groups from week 4 to 14 after primary immunization (p<0.05). No significant difference was observed at weeks 22 and 30 after the primary immunization. Similar results were also found for scrotal circumference, testicular weight, length, breadth, and spermatogenesis in seminiferous tubules in week 30 after primary immunization. KS (KISS1-hepatitis B surface antigen S) fusion fragment of KISS1 gene vaccine was not detected in host cell genomic DNA of 9 tissues of the vaccinated ram lambs by polymerase chain reaction.

Conclusion

The effects of KISS1 gene vaccine in immunocastration were reversible and no integration events were recorded.

Quantifying production, processing and post-slaughter effects on pork eating quality using random effects meta-regression

Random effects meta-regression techniques, analyzed using a restricted maximum likelihood (REML) approach, was used to determine the influence of various factors that may be experienced or imposed on pigs, carcases and pork on pork eating quality attributes and shear force of the M. longissimus dorsi (loin). This was done to inform the development of a pathway based eating quality system for pork. Estimated means of explanatory variables were obtained for those pathway factors where sufficient published studies met the criteria for inclusion in the analysis. Due to a lack of data for interactions between factors investigated, only single factors were included as fixed terms in the REML models. This analysis identified that moisture infusion (P < 0.001), ageing for more than 2 d post-slaughter (P = 0.006) and tenderstretching (P = 0.006) each resulted in significant improvements in tenderness. Cooking loins to an endpoint temperature of ≥ 80°C negatively impacted both tenderness (P = 0.022) and juiciness (P < 0.001) scores compared with 70 to 74°C. It was not possible to develop algorithms to reliably estimate the effects of multiple factors on pork eating quality attributes to a cuts-based level due to limited studies reporting data for treatment interactions.

Eating quality traits of shoulder roast and stir fry cuts outperformed loin and silverside cuts sourced from entire and immunocastrated male pigs

This study investigated the effects of ageing period (2 or 7days), endpoint temperature (70 or 75°C), cut type (loin (M. longissimus thoracis et lumborum), silverside (M. biceps femoris), blade (M. triceps brachii) and chuck tender (M. supraspinatus)), cooking method (roast and stir fry (all cuts) and steak (loin only)) on eating quality attributes of pork from entire and immunocastrated male pigs. Higher intramuscular fat levels were found in all cuts from immunocastrated males compared with entire males. Of the seven cut type×cooking method combinations evaluated, shoulder cuts had the lowest fail rate (P<0.001) and loin steak and silverside cuts scored lowest (P<0.001) for tenderness, juiciness, overall liking, quality grade and re-purchase intention. Although no differences in sensory scores due to gender were observed, boar taint was identified in 10% of entire males. Minimising adverse risks in eating quality due to boar taint in males remains a key industry issue to ensure consistent delivery of high quality pork.

Diet composition and slaughter age up to 24weeks have minimal impact on pork eating quality of loin steaks and silverside roasts from female pigs

Female crossbred pigs were randomly allocated at 16weeks of age to one of three dietary treatments (A: corn and soybean meal; B: wheat and canola meal; C: wheat and sorghum) matched for digestible energy (13.6MJ DE/kg) and total lysine (0.93-0.95%) and fed for 4, 5 or 8weeks, respectively, prior to slaughter. Loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) were obtained from 20 pigs per dietary treatment group and prepared into steaks and roasts, respectively, for consumer evaluation with ageing treatments of 7 and 28days post-slaughter allocated within muscle. Neither dietary treatment/age at slaughter nor ageing treatment influenced sensory traits of either cut. Intramuscular fat levels were also not influenced by dietary treatment. Higher (P<0.001) fail rates for silverside roasts compared with loin steaks indicate that different interventions are needed at a cut level to optimise pork eating quality consistency and consumer expectations.

Guaranteeing consistently high quality Australian pork: are we any closer?

Considerable investment has been made by the Australian pork industry over several decades, to address key factors that affect pork quality, so as to improve consumer acceptability of pork and pork products. These outcomes have been utilised to inform on-farm quality assurance programs, develop effective solutions to negate boar taint issues associated with the production of entire males, drive continuous improvement in animal management and encourage new technologies to be implemented in both the production and processing sectors of the Australian pork supply chain. Australian Pork Limited’s Strategic Plan 2015–20 is focused on maintaining profitable and sustainable growth in existing markets and developing strong foundations to support new opportunities, both in Australia and internationally. Guaranteeing that pork available for purchase is always consistently high in eating quality will support ongoing consumer demand for pork through increased consumption frequency. However, achieving this on an everyday basis presents industry with significant challenges due to the many complex interactions among the production, processing and post-slaughter factors experienced by pigs, carcasses and pork that can influence final product quality, either singularly or in combination. The present paper describes recent quantitative studies to determine the size and effect of pathway parameters on eating quality attributes of fresh pork and knowledge gaps identified. Outcomes of consumer sensory studies to inform the development of a non-prescriptive cuts-based eating quality system for pork and commercially validate particular pathway interventions are detailed. Through the implementation of validated pathway interventions to optimise pork eating quality, the overall industry objective is to reduce eating quality fail rates of different pork cuts to less than 10%.