The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study

Improving Beef Cattle Production: Safety and Effectiveness of New Immunocastration Vaccine

Reproductive control in mammals, particularly in beef production systems, is crucial for managing behaviors driven by sex steroids, which can cause biosecurity issues, reduced weight gain, and decreased meat quality. Additionally, controlling sexual activity in females prevents unwanted pregnancies when both sexes are housed together for fattening. Surgical castration in cattle, commonly performed under field conditions, is associated with significant welfare concerns due to pain and infection risks. Furthermore, castrating female cattle in the field is often impractically expensive. Hence, new reproductive control methods that prioritize animal welfare and are suitable for both sexes are essential. Immunocastration (IC), which involves vaccination against the GnRH-I hormone, has emerged as a promising alternative, demonstrating efficacy and safety in various species. Immunocastration has proven to be an effective alternative to surgical castration in controlling reproduction and promoting animal welfare in several species. This study aims to evaluate the safety, immunogenicity, immunocastration effect, and productive impact of a novel IC vaccine developed in Chile for female cattle. Two consecutive trials were conducted, the first under controlled conditions and the second under field conditions. The results demonstrated that the new vaccine is safe and effective for use in beef cattle, inducing specific immunity against GnRH-I, reducing gonadal functionality, and improving productive parameters. These findings suggest that this new IC vaccine can significantly benefit the beef cattle industry by providing a welfare-friendly and efficient method of reproductive control.

Heavy Pigs Reared for Italian Dry-Cured Products: Does Immunocastration Influence the Fatty Acid Profile of Loins and Backfat?

The Italian pig sector requires heavy pigs (raised for at least nine months and slaughtered at >160 kg). In order to avoid boar taint and lower the impact on welfare, immunocastration provides an alternative to surgical castration. This study investigated the effects of immunocastration compared to surgical castration on the chemical composition and fatty acid profile of loins (longissimus dorsi muscle) and adipose tissue in Italian heavy pigs raised for dry-cured ham. Twenty-four male pigs were subjected to surgical castration (n = 12) or immunocastration (n = 12). Carcass parameters were monitored at slaughter, and samples of longissimus dorsi muscle and subcutaneous fat were analysed. This study showed no significant differences in carcass characteristics and proximate composition of fresh meat. However, variations were observed in the fatty acid profiles of meat and adipose tissue between groups. Notably, saturated fatty acids, particularly stearic acid (18:0), were higher in the intramuscular fat (IMF) of the immunocastrated pigs compared to the surgically castrated pigs. Conversely, monounsaturated fatty acids, predominantly oleic acid (18:1n-9), were higher in the IMF from the surgically castrated pigs compared to the immunocastrated pigs. While immunocastration may offer benefits in terms of animal growth and carcass composition, it could lead to unfavourable lipid changes in fresh loin meat for Italian heavy pigs.

The effects of different immunocastration protocols on meat quality traits and boar taint compounds in male Bísaro pigs

Immunocastration can be an alternative to surgical castration in Bísaro pigs when there is a need to keep animals on the farm until at least 8 months old. As an autochthonous breed, some particularities must be addressed when doing immunocastration, for which 3 different protocols were tested and two control groups were made with surgically castrated males (SC) and boars (Bo). Two protocols were made in prepubertal pigs, with two (E2) and three inoculations (L3) in the first cycle, and another in adults (A2) with only two inoculations. Physicochemical parameters and boar taint compounds quantification and sensory analysis of the meat from the studied pigs were assessed. Immunocastration provided intermediate values between surgically castrated pigs and entire males, with low levels of boar taint compounds. The L3 group provided closer results to SC, which was also corroborated by the sensory analysis. Although the other two protocols had no significant differences with Bo, there was a positive tendency towards them. As is, the L3 protocol was promising as a good alternative to surgical castration, maintaining the characteristic attributes of the Bísaro pig meat.

Effect of Immunocastration on Culled Sows-A Preliminary Study on Reproductive Tract, Carcass Traits, and Meat Quality

The Bísaro pig is a Portuguese autochthonous breed greatly appreciated for its meat quality and is mainly reared outdoors. Immunocastration could be a solution to avoid undesirable pregnancies and boar taint in cull sows. The present study tested three immunocastration protocols (with Improvac®) according to their reproductive cycle. The first inoculation was performed two weeks after farrowing (IM1, n = 5), at the beginning of estrus (IM2, n = 5), and one week after the end of estrus (IM3, n = 5), followed by a second administration four weeks apart. A control group (C, n = 5) was also included in the same housing conditions. The sample collection included the reproductive tract for morphometric evaluation, neck fat for the quantification of boar taint compounds, and a portion of the Longissimus thoracis et lumborum for meat quality trait assessment. The reproductive tracts from intact sows (C) were significantly heavier compared to the immunocastrated groups (p < 0.05) (1.403 kg C to 0.508 kg IM1, 0.590 kg IM2, and 0.599 kg IM3), suggesting the regression of the reproductive tract to nonstimulated conditions due to immunization against GnRH. The IM1 group exhibited significantly smaller reproductive tract measurements compared to group C for most of the evaluated segments (p < 0.05). No marked differences were observed in the meat quality traits. Therefore, immunocastration can be used in culling sows to avoid ovarian activity, and it is not detrimental to pork quality traits.

Effect of Castration Type and Diet on Growth Performance, Serum Sex Hormones and Metabolites, and Carcass Quality of Heavy Male Pigs

A trial was carried out to study the effect of type of castration and diet on pigs destined for Teruel ham production, which is a Spanish protected designation of origin for dry-cured ham. A total of 144 Duroc × (Landrace × Large White) male pigs were used. Half of them were surgically castrated and the other half were immunocastrated with three doses at approximately 25, 58 and 79 kg of body weight. Furthermore, three diets (control vs. high energy vs. low crude protein-CP- and amino acids-AA) were tested from 80 to 137 kg of body weight. Growth performance, serum sex hormones and metabolites, and carcass quality were evaluated. Immunocastrated males grew faster and had better feed conversion ratio than surgically castrated males, but presented lower carcass fatness. Pigs fed the high-energy diet and the low-CP and -AA diet were more efficient at transforming feed into gain than those fed the control diet, but no effect was detected on carcass quality. In conclusion, surgically castrated males are preferable than immunocastrated males for Teruel dry-cured ham elaboration. Besides, a high-energy diet or a low-CP and -AA diet might improve productive performances, but does not provide any benefit in terms of carcass quality.

Consumers' Expectations about Meat from Surgical Castrated or Immunocastrated Male and Female Iberian Pigs

A common practice in Iberian pigs is the castration of both males and females, and it can be carried out surgically or by immunization against gonadotropin-releasing factor (GnRF). The aim of this work was to determine consumers' overall liking and expectations towards Iberian pork from five different sex types (castrated females, entire females, GnRF-vaccinated females, castrated males and GnRF-vaccinated males), as well as to know the attitudes and beliefs of consumers towards castration and immunocastration. Loins from 83 Iberian pigs were collected and evaluated by 252 consumers in Barcelona and Madrid. Consumers evaluated the five types of meat in three situations: blind condition (tasting the product), expectations (without tasting) and informed condition. Finally, attitudes and beliefs towards castration and immunocastration were also determined. Results distinguished three segments of consumers labeled as "Indifferent", "Against castration and immunocastration" and "Against immunocastration". Meat from castrated males had higher overall liking scores in the blind condition. Expectations towards pork depending on its sex type affect consumer-informed acceptability; thus, it is important to consider marketing strategies to avoid or direct the effect of the information provided on the acceptability of the pork.

Influence of Immunocastration and Diet on Meat and Fat Quality of Heavy Female and Male Pigs

Two experiments were carried out; one with female pigs and the other with male pigs destined for Teruel dry-cured ham production, to evaluate the effect of immunocastration (entire gilts-EG vs. immunocastrated gilts-IG and surgically castrated males vs. immunocastrated males-IM) and diet (control vs. high energy vs. low crude protein and amino acids) on meat quality and fat composition. Fifteen meat samples and eight fat samples of each treatment were analyzed in both experiments. In the case of males, six fat samples per treatment were analyzed to determine boar taint. Immunocastration is a good strategy in gilts intended for dry-cured ham production because improves meat composition; however, in males, immunocastration impairs the results of pork chemical composition compared with surgical castration. The IG presented a lower polyunsaturated/saturated fatty acids ratio than EG, improving fat technological quality. Diets had little effect on pork or fat quality in gilts, but a high-energy level using oilseeds and a low-crude-protein and -amino-acids diet from 80 to 137 kg of body weight could be interesting in IM to maintain or increase fat consistency, respectively. Moreover, in general, immunocastration is effective in avoiding boar taint in males.

Effect of Immunocastration and Diet on Growth Performance, Serum Metabolites and Sex Hormones, Reproductive Organ Development and Carcass Quality of Heavy Gilts

It is desirable to increase fatness in gilts destined for Teruel dry-cured ham production. A total of 192 Duroc × (Landrace × Large White) gilts of 40.3 ± 4.80 kg body weight (BW) were used to assess the impact of immunocastration and feeding on growth performance, serum metabolites and sex hormones, reproductive organ development, and carcass quality. Six treatments were arranged factorially (2 × 3) with two types of gilt (entire gilts (EG) vs. immunocastrated gilts (IG)) and three experimental diets (control vs. high energy vs. low crude protein and amino acids) provided from 76 to 134 kg BW (n = 4 per treatment, being the replicate the pen with eight pigs). Immunocastration was carried out at 58 and 77 kg BW. The IG grew faster and showed lighter reproductive tracts and greater fatness than EG. The experimental feeds had limited effect on carcass quality, but the high-energy diet improved gain-to-feed ratio and the low-protein and -amino-acids diet did not impair growth performance. In conclusion, immunocastration was a better strategy than the tested diets to increase the fatness of gilts intended for Teruel dry-cured ham, although increasing energy or decreasing crude protein and amino acid levels in the diet could be beneficial strategies for pig farmers.

Effects of L-Glutamine Supplementation during the Gestation of Gilts and Sows on the Offspring Development in a Traditional Swine Breed

Simple Summary

Nutritional strategies during pregnancy in swine production are considered essential to increase the number of piglets born alive and improve their survival and development. Amino acids, such as glutamine, are among the best compound to introduce in commercial farms after obtaining positive results in trials carried out in selected swine breeds. However, several critical productive factors have to be assessed before translating these strategies to the farm level to ensure the best balance between benefits and investments. The current study focused on the effects of prenatal L-glutamine supplementation on the offspring of Iberian gilts and sows under farm conditions. It is the first trial of amino acid supplementation during pregnancy carried out in traditional swine breeds. These non-selected swine breeds show productive or physiological differences that could affect the supplementation effect. Indeed, although there were changes at the molecular and tissue level, these effects did not turn into advantageous effects for the offspring of traditional breeds. The present study shows the importance of pre-testing nutritional strategies under the final conditions and breeds of implementation and the need to deepen at the molecular level to improve the biological interpretation of findings.

Abstract

The use of amino acids during pregnancy, such as glutamine (Gln), seems to be a promising strategy in selected swine breeds to improve the offspring prenatal development. The main goal of the current study was to assess the development of the offspring from parity 1–3 sows of a traditional breed, which were supplemented with 1% glutamine after Day 35 of gestation, under farm conditions. A total of 486 (288 treated) piglets from 78 (46 treated) Iberian sows were used. At birth and slaughterhouse, fatty acid composition, metabolism, and mTOR pathway gene expression were analyzed. At birth, treated newborns showed greater amounts of specific amino acids in plasma, such as glutamine, asparagine, or alanine, and Σn-3 fatty acids in cellular membranes than control newborns. The expression of genes belonging to mTOR Complex 1 was also higher in treated piglets with normal birth-weight. However, these findings did not improve productive traits at birth or following periods in litters from supplemented gilts (parity 1) or sows (parities 2–3). Thus, further research is needed to properly understand the effects of prenatal glutamine supplementation, particularly in traditional swine breeds.

Can Hydrolysable Tannins in Diet of Entire Male Pigs Affect Carcass, Pork Quality Traits, Amino and Fatty Acid Profiles, and Boar Taint, Skatole and Androstenone Levels?

The slaughtering of entire males increases the probability of incidence of tainted pork due to the presence two main compounds-androstenone and skatole. If a surgical castration of young entire male pigs is stopped in the EU countries, fattening of boars is likely to become one of the most commonly used systems in pig farming. Since skatole production and accumulation in fat tissue can be controlled by dietary approaches, several studies have investigated various feed additives to reduce this compound of boar taint. Ones of the most promising is tannins. The aim of this study was to determine the effect of different dietary tannin level supplementation on carcass, pork quality, chemical, amino and fatty acid composition. as well as perception of boar taint and accumulation of skatole and androstenone in adipose tissue. Eighty entire males were randomly distributed to control (T0) and four experimental groups. Control pigs received standard feed mixture (16.8% CP, 13.9 MJ ME) without any tannin supplementation. Experimental pigs received the same diet with administration of 1% (T1), 2% (T2), 3% (T3) and 4% (T4)-sweet chestnut extract rich in hydrolysable tannins for 40 days (from average live weight of 80 kg until slaughter at average weight 122.28 kg ± 5.63 kg). Dietary tannins supplementation did not show any significant effect on chemical composition, cholesterol content, and amino acid composition of muscle as well as fatty acid composition and androstenone accumulation in adipose tissue. A slight or small effect was observed on carcass and meat quality, respectively. Pigs in groups T4 and/or T3-T4 had higher electrical conductivity in semimembranosus muscle and cooking loss value compared to T1, T2 or T0, T1, and T2 groups (p < 0.05). Tannins in the pig's diet greatly affected fatty acid profile in meat of entire males. The highest tannin levels (4%) increased concentrations of lauric, myristic, vaccenic, linoleic, total PUFA, and n-6 PUFA in muscle compared to the control. Similar results were found in group T3 except for vaccenic, linoleic, and total PUFA. On the contrary, concentrations of heptadecanoic and oleic acids in groups T3 and T4 were lower than those in T1 and T2 groups. Perception of boar taint using "hot iron" method (insertion a hot iron tip of soldering iron into adipose tissue) tended to decrease in T2 group compared with control. Skatole accumulation in fat tissue was reduced in groups T2-T4 at significance level (p = 0.052-0.055) compared to the control pigs. In summary, tannins supplementation had no effect on chemical and amino acid composition as well as fatty acid profile in adipose tissue, and only slight on carcass value. However, 4% concentration of tannins significantly increased content of some fatty acids compared to control group.

Long-Term Immunocastration Protocols Successfully Reduce Testicles' Size in Bísaro Pigs

Simple Summary

Surgical castration is an ongoing problem in pig production, especially in breeds reared until older ages, like the Bísaro pig. To avoid this technique, three immunocastration protocols with different numbers of injections and times of inoculation were tested. Scrotal measurements were used to attest their effectiveness. The best protocol was the one with three administrations starting at three months old. It was able to maintain the testis size below puberty size for 16 weeks following the last injection.

Abstract

This study aimed to find a suitable immunocastration protocol for male Bísaro pigs (BP) due to the breed and production system particularities. Twenty-five male BP were treated with Improvac^® according to three protocols: using two (GrpE2 and L2) or three vaccinations (GrpL3) and starting at 9 (GrpE2) or 13 weeks old (GrpL2 and L3). Eleven animals were kept as intact males (GrpC). Scrotal measurements and the morphometry of the testes and epididymides collected at slaughter were used to survey the effectiveness of the immunocastration compared with the age-matched intact controls. Animals in groups E2 and L3 were kept until 57 weeks, after a second vaccination cycle at 49 and 53 weeks of age. Scrotal dimensions decreased to almost initial values in treated animals until 17 (GrpE2) and 21 weeks (GrpL2 and L3), thereafter increasing to post-pubertal values until around 29 or 37 weeks of age for groups E2 and L2, respectively, but only at 41 weeks in group L3. Between 41 and 49 weeks, scrotal dimensions were similar in treated and control animals, decreasing to the predicted pre-puberty size after the second cycle of vaccination. This study suggests the most suited protocol for males slaughtered at older ages includes three administrations of Improvac^® starting at 3 months of age, followed by a second vaccination cycle.

Immunocastration in Gilts: A Preliminary Study of the Effect of the Second Dose Administration Time on Growth, Reproductive Tract Development, and Carcass and Meat Quality

Simple Summary

Nowadays, a significant proportion of pig carcasses destined to high-quality dry-cured ham elaboration are declared unsuitable for this purpose. The main reason is the lack of backfat thickness, affecting females in particular because males are castrated. Moreover, the estrus in gilts is undesirable because it carries out productive losses. Immunocastration could resolve these problems. The protocol of immunocastration in white-breed gilts is not well established, especially in terms of the second injection. Therefore, the objective of the current trial was to evaluate the impact of immunocastration and to determine the optimum time for the second dose application in gilts intended for dry-cured ham production. In this trial, we concluded that gilt immunocastration is positive, increasing carcass fatness and decreasing reproductive tract development. Moreover, the optimum time to administer the second dose of immunocastration for this type of gilt seems to be between 9 and 12 weeks before sacrifice.

Abstract

Increasing fatness and avoiding puberty are desirable in gilts intended for high-quality dry-cured ham production. A total of 48 Duroc x (Landrace x Large White) females of 26.5 ± 3.70 kg body weight (BW) were used to evaluate the impact of immunocastration and to find the optimum application time of the second dose for immunocastration on growth; sex hormones; reproductive tract development; and carcass, meat, and fat quality. Gilts were allocated to four experimental treatments (n = 12): control (entire gilts, EG) and immunocastrated gilts (IG), providing the second dose at 12, 9, or 7 weeks before slaughter (with approximately 60, 75, or 90 kg BW, respectively). Mean slaughter BW was 125 kg. Immunocastrated gilts had lighter reproductive tracts and greater fat thickness than EG. Fat from IG was more saturated and less polyunsaturated than that from EG. Numerically, gilts immunocastrated 9 and 12 weeks before slaughter presented higher fatness than those immunocastrated 7 weeks before slaughter. In conclusion, immunocastration is a good strategy to improve the fatness of gilts destined to dry-cured ham elaboration, with the optimum time for the second dose application seemingly between 9 and 12 weeks before slaughter.

Influence of Immunocastration on Slaughter Traits and Boar Taint Compounds in Pigs Originating from Three Different Terminal Sire Lines

Simple Summary

Due to the negative public opinion and welfare issues related to surgical castration, gradual introduction of alternatives like entire males and immunocastrates is taking place. Despite several economical and welfare advantages that the alternatives offer, numerous issues (i.e., boar taint, meat quality alterations), as well as their interactions with rearing and breeding (genetic) factors remain unanswered. Therefore, the focus of this study was to investigate the possibility of using different commercial sire lines in three male sex categories (entire males, immunocastrates, surgical castrates) and to compare their carcass traits, meat quality and boar taint compounds. A significant effect of terminal sire line and/or male category together with their interaction was observed for most of the investigated carcass and meat quality traits. The observed interaction should be taken into consideration when deciding on the production of a specific male category.

Abstract

The aim of the research was to investigate the influence of terminal sire line (TSL) and male category (MC) on carcass and meat quality of commercial fatteners. The study was performed on 180 pigs originating from three terminal sire lines: A (Pietrain × Large White), B (pure Pietrain), and C (Pietrain × Duroc × Large White), being assigned to three groups according to MC: immunocastrates (IC, n = 60), surgical castrates (SC, n = 60) and entire males (EM, n = 60). TSL affected most of the carcass and meat quality traits, together with the androstenone concentration. At the same time, MC had a significant effect on fat thickness, ham circumference, drip loss, cooking loss and androstenone and skatole concentrations. A significant interaction effect was observed for carcass length and ham circumference, as well as for most of the measured meat quality traits (except cooking loss, CIE L*, CIE b*, and Warner Bratzler Shear Force (WBSF)). Among the three investigated sire lines, immunocastration was shown to be most beneficial for fatteners sired by the TSL C. However, if deciding to raise EM, fatteners from the TSL B are recommended in terms of carcass and meat quality, although strategies for avoiding boar taint in their carcasses must be taken into consideration.

The Role of Offspring Genotype-By-Sex Interactions, Independently of Environmental Cues, on the Phenotype Traits of an Obese Swine Model

Simple Summary

The present study, comparing the postnatal development of purebred Iberian and crossbreds Iberian × Large White littermates born from purebred Iberian sows, allows us to discern phenotype traits driven by the genotype from features imposed by pre- and postnatal environment. The results obtained in this study support the well-known relevance of genotype but also evidence a paramount role of the interaction sex-by-genotype, with differential effects depending on the offspring genotype and sex.

Abstract

The present study aimed to assess the importance of offspring genotype on postnatal development, independently of confounding factors related to prenatal environment and postnatal lifestyle, using a translational model of obesity and metabolic syndrome (the Iberian pig). Hence, we compared two genotypes (purebred Iberian and crossbreds Iberian × Large White), produced in one single maternal environment (pure Iberian mothers) through artificial insemination of Iberian sows with Iberian and Large White heterospermic semen and maintained in the same conditions during postnatal development. The results indicate that, under same pre- and postnatal environments, the interaction genotype-by-sex has a determinant role on offspring phenotype (i.e., growth and development, metabolic and antioxidant status and fatty acid composition of different tissues). These results may set the basis for future preclinical and clinical research on the differences in the metabolic phenotype among genotypes.

Maternal Supplementation with Polyphenols and Omega-3 Fatty Acids during Pregnancy: Effects on Growth, Metabolism, and Body Composition of the Offspring

Simple Summary

The present study aimed to determine benefits and risks of a dietary supplementation combining hydroxytyrosol and n3 polyunsaturated fatty acids (PUFA) on developmental patterns and metabolic traits of offspring in swine, a model of intrauterine growth restricted (IUGR) pregnancies. There were no deleterious effects on the reproductive traits of the sows and the postnatal features of the piglets. Piglets from the supplemented sows, in spite of a lower mean weight and corpulence at birth, showed higher average daily weight gain and fractional growth rate afterwards. Consequently, they reached higher weight and corpulence with increased muscle development and better lipidemic and fatty acids profiles than control offspring at juvenile stages.

Abstract

Maternal supplementation with antioxidants and n3 PUFAs may be a promising strategy to reduce the risk of intrauterine growth restriction and preterm delivery, which may diminish the appearance of low-birth-weight neonates. The present study aimed to determine benefits and risks of a dietary supplementation combining hydroxytyrosol, a polyphenol from olive leaves and fruits, and n3 PUFAs, from linseed oil, on developmental patterns and metabolic traits of offspring in swine, a model of IUGR pregnancies. The results obtained indicate that maternal supplementation with hydroxytyrosol and n-3 fatty acids during pregnancy has no deleterious effects on the reproductive traits of the sows (prolificacy, homogeneity of the litter, and percentage of stillborns and low-birth-weight, LBW, piglets) and the postnatal features of the piglets (growth patterns, adiposity, and metabolic traits). Conversely, in spite of a lower mean weight and corpulence at birth, piglets from the supplemented sows showed higher average daily weight gain and fractional growth rate. Thus, at juvenile stages afterwards, the offspring from the treated group reached higher weight and corpulence, with increased muscle development and better lipidemic and fatty acid profiles, in spite of similar adiposity, than offspring in the control group. However, much caution and more research are still needed before practical recommendation and use in human pregnancies.

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.

The Implications of Nutritional Strategies that Modify Dietary Energy and Lysine for Growth Performance in Two Different Swine Production Systems

Simple Summary

Reducing dietary energy is a common practice for dealing with the price volatility of high energy sources, such as fats and oils, which are the costliest constraints in swine feed formulation. Theoretically, pigs can overcome a reduced energy density by increasing feed intake; however, as other factors like fibrous ingredients limit feed intake physically rather than metabolically, reducing dietary energy could also entail a lower energy intake. The expected effect on feed intake also influences lysine intake, and therefore, when NE trials are conducted, it is necessary to ensure that lysine is not a limiting factor for growth. In the present work, the effects of two dietary energy and lysine levels were tested in a factorial arrangement. The same approach of different levels was analyzed in two different swine production systems targeting different carcass traits. The experiment showed that in one system, reducing energy density did not impair growth; however, in the other system, it limited growth slightly by limiting fat deposition. Although reducing energy density increased feed intake, pigs could not reach a similar energy intake, and consequently were more efficient using energy for growth.

Abstract

This work aimed to determine the impacts of lowering dietary net energy (NE) density in two swine production systems that produce pigs with different carcass traits. To ensure that dietary lysine was not limiting growth, two studies were conducted in a 2 × 2 factorial arrangement with NE and standardized ileal digestible lysine (SID Lys) as experimental factors. A total of 1248 pigs were used in each study, Pietrain (Exp. 1, males non-castrated) or Duroc (Exp. 2, males castrated) sired. Reducing NE resulted in a greater feed intake; however, this was not sufficient to reach the same NE intake. While in Exp. 1 a 3.2% lower NE intake did not impair average daily gain (ADG; p = 0.220), in Exp. 2 a 4.7% lower NE intake reduced ADG by 1.4% (p = 0.027). Furthermore, this effect on ADG entailed a reduced ham fat thickness (p = 0.004) of the first marketed pigs. Increasing SID Lys only had a positive effect in Exp. 1, but no significant interaction between NE and SID Lys was reported (p ≥ 0.100). Therefore, dietary NE can be reduced without impairing growth performance when pigs can increase feed intake sufficiently, and thus, limit energy deficiencies.

Short-Term Effects of Early Menopause on Adiposity, Fatty Acids Profile and Insulin Sensitivity of a Swine Model of Female Obesity

Menopause strongly increases incidence and consequences of obesity and non-communicable diseases in women, with recent research suggesting a very early onset of changes in lipid accumulation, dyslipidemia, and insulin resistance. However, there is a lack of adequate preclinical models for its study. The present trial evaluated the usefulness of an alternative method to surgical ovariectomy, the administration of two doses of a GnRH analogue-protein conjugate (Vacsincel^®), for inducing ovarian inactivity in sows used as preclinical models of obesity and menopause. All the sows treated with the compound developed ovarian stoppage after the second dose and, when exposed to obesogenic diets during the following three months, showed changes in the patterns of fat deposition, in the fatty acids profiles at the different tissues and in the plasma concentrations of fructosamine, urea, β-hydroxibutirate, and haptoglobin when compared to obese fed with the same diet but maintaining ovarian activity. Altogether, these results indicate that menopause early augments the deleterious effects induced by overfeeding and obesity on metabolic traits, paving the way for future research on physiopathology of these conditions and possible therapeutic targets using the swine model.

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.

Piglet birthweight and sex affect growth performance and fatty acid composition in fatty pigs

This study aimed to determine the effects of piglet birthweight (BIW) and sex, and within-litter BIW variation, on postnatal growth traits and meat quality in fatty breeds of pig. In total, 406 crossbred piglets (half male, half female) born to Iberian sows were studied during their postnatal development until slaughter. After birth, piglets were classified into four BIW categories: very low, low, medium and high. There was a negative effect of low BIW on growth patterns and fatty acid (FA) composition, but effects of litter size and within-litter BIW variation were not found. The very low BIW piglets underwent a period of significant catch-up growth (P &lt; 0.005) relative to high BIW piglets during the early postnatal phase, but also showed a higher feed conversion rate and lower average daily weight gain (P &lt; 0.05 for both measures) throughout the study period. BIW affected development during the entire productive life, and the sex effect increased with age. As a result, the period to reach market weight was longer in very low BIW piglets, by 43 days for females and 15 days for males, compared with their high BIW counterparts. BIW and sex also influenced amount of intramuscular fat, n-3 FA content and monounsaturated FA composition. The study indicates that BIW, modulated by sex, is a critical point for productive traits in fatty pigs. These results provide a basis for future strategies to enhance productive efficiency and meat quality of traditional swine breeds.

Sustainability of Pork Production with Immunocastration in Europe

Immunocastration, a technique to replace surgical castration of piglets, consists of two consecutive vaccinations to induce antibodies which transiently suppress testicular functions and avoid boar taint. It is a method to ensure both a high product quality and a high level of animal welfare. The impact of immunocastration on the three pillars of sustainability has been studied extensively. While all aspects of sustainability have been studied separately, however, a contemporary global overview of different aspects is missing. In immunocastrates, performance results are better than in barrows, but worse than in boars. The environmental impact of pork production with immunocastrates is lower than with barrows, but higher than with boars. The level of aggression is considerably lower in immunocastrates compared to boars. Societal concerns are mainly related to food safety, and are not supported by scientific evidence. After second vaccination, immunocastrates switch from a boar- to a barrow-like status. Therefore, the timing of second vaccination is a fine-tuning tool to balance advantages of boars with environmental and economic benefits against increased risk of welfare problems and boar taint. Nevertheless, both synergic and conflicting relationships between the pillars of sustainability must be communicated along the value chain to produce tailored pork products.

Impact of sexual maturity on the welfare of immunocastrated v. entire heavy female pigs

During oestrus, fattening female pigs are more prone to lameness, fractures and wounds due to mounting and agonistic behaviours of penmates. This study assessed the effect of sexual maturity on the behaviour and welfare of heavy female pigs slaughtered at 36 weeks of age (180±10 kg) for dry-cured ham production. An immunocastrated control group was used for comparison. In all, 56 15-week-old female pigs, individually identifiable by back tattoos were equally distributed among four pens. All animals from two pens were subject to a three-dose immunocastration schedule at 16, 20 and 32 weeks of age. Skin lesions and behaviours were assessed at 18, 23, 28, 33 and 36 weeks of age. A blood sample was collected at 20, 24, 28 and 32 weeks of age for assessing health/stress parameters and GnRH antibodies. At slaughter, ovaries were weighed, measured and histologically examined; stomachs, carcasses and lungs were scored for lesions and a further blood sample was taken. Immunocastrated pigs did not significantly differ from controls in growth rate, feed efficiency and slaughter performances (lung score, gastric score, backfat thickness). However, they showed a lower frequency of aggressive interactions at 33 and 36 weeks, lower front lesions at 28 weeks, but higher at 30 weeks; a lower haptoglobin level at 28 weeks, a lower level of cortisol and back lesions at slaughter (36 weeks). These findings suggest a low, yet not negligible, impact of sexual maturity on the welfare of heavy female pigs.