Search Results (72)

Gonad loss triggers severe endocrine disorders and altered energy metabolism, yet the precise mechanisms remain poorly understood. In swine production, surgical castration is widely performed to eliminate boar taint and aggressive behavior, but it impairs feed efficiency, increases fat deposition, and raises animal welfare issues. Castration reduces testosterone and estrogen levels, leading to elevated gonadotropin-releasing hormone (GnRH) and its downstream follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Traditionally viewed as a reproductive hormone, FSH has recently emerged as a critical regulator of peripheral metabolism. Based on these findings, we designed and developed a novel FSH vaccine comprising an FSHβ13AA-tandem-ovalbumin conjugate, which has been demonstrated to effectively regulate growth and metabolism in castrated boars. In conclusion, this review underscores the previously underrecognized metabolic functions of follicle-stimulating hormone (FSH) and proposes a novel immunomodulatory strategy targeting FSH for fine-tuning organ function and energy metabolism. This approach shows considerable potential for advancing sustainable, welfare-oriented swine production. Full article

Castration is widely used in goat production to improve meat quality and manage reproduction, yet conventional surgical methods raise significant animal welfare concerns. Immunocastration targeting gonadotropin-releasing hormone (GnRH) offers a promising, welfare-friendly alternative, but its efficacy in slow-growing indigenous breeds remains poorly defined. In this study, we developed a novel tandem-repeat GnRH(30) recombinant vaccine and evaluated its effects on growth performance, reproductive function, and meat quality in male Leizhou goats. Eighteen six-month-old bucks were assigned to an immunocastration group (IM), surgical castration group (SC), or intact control group (IC). Vaccinated goats produced sustained anti-GnRH antibodies and exhibited significantly suppressed testosterone levels comparable to surgical castrates. Immunocastration induced marked testicular atrophy, disrupted spermatogenesis, reduced semen volume and sperm motility, and increased sperm abnormalities. Importantly, early growth performance and final body weight were not significantly affected. Compared with intact males, both IM and SC goats showed improved meat quality traits, including reduced drip loss and shear force, accompanied by increased intermuscular fat deposition, with overall patterns in the IM group closely resembling those of surgical castration. Overall, these findings indicate that the GnRH(30) vaccine can effectively suppress spermatogenesis and improve meat quality without affecting growth, providing an effective technical approach for castration management in indigenous goats. Full article

Despite their substantial contributions to herd productivity, culled sows typically receive minimal economic valorisation. This study evaluated the feasibility of finishing culled Iberian sows under free-range conditions (montanera finishing system) and assessed the effects of immunocastration on productivity, welfare, and meat quality. Thirty-six culled Iberian sows were assigned to two treatments: entire sows (n = 18) and immunocastrated sows (n = 18). Following a maintenance phase and a pre-finishing transition, animals were finished under montanera conditions with ad libitum access to acorns and pasture. Productive traits, welfare indicators, carcass traits, and meat quality parameters were evaluated. Immunocastration effectively suppressed reproductive function without compromising productive traits or meat quality in culled Iberian sows. Both groups exhibited comparable body weight evolution, carcass characteristics, and meat quality attributes consistent with Iberian standards. The results indicate a clear potential for value generation, transforming animals from minimal-value culling categories to premium montanera products. This integrated approach combining immunocastration with traditional extensive finishing systems provides a viable way to add value to culled sow valorisation within circular economy frameworks, addressing economic, environmental, and welfare challenges of sustainable livestock production. Full article

Dog overpopulation poses serious challenges to public health, animal welfare, and environmental sustainability. While surgical castration remains the most commonly used method for controlling reproduction in dogs, it carries risks and limitations, including surgical complications and long-term behavioral or physiological side effects. This review examines the potential of immunocastration—vaccination targeting gonadotropin-releasing hormone (GnRH)—as an alternative approach. Immunocastration has been shown to suppress reproductive hormones, reduce gonadal function, and decrease behaviors such as roaming, aggression, and sexual mounting in dogs. The review also includes evidence from other species (e.g., pigs, cattle, and horses) to contextualize effectiveness and welfare implications. While behavioral effects are more variable and less frequently studied than physiological outcomes, recent findings suggest immunocastration may have fewer negative emotional side effects (e.g., anxiety and stress-related behaviors) than surgical sterilization. The review highlights the mechanisms, applications, and behavioral outcomes of immunocastration, including its reversibility, cost-effectiveness, and suitability for mass implementation. Overall, immunocastration offers a promising addition to dog population management strategies, particularly in regions with limited surgical infrastructure. Future research should focus on standardizing vaccine protocols and assessing long-term behavioral and welfare outcomes in diverse dog populations. Full article

Surgical castration, a common practice in animal husbandry, raises animal welfare concerns and adversely affects growth performance. Active immunization against gonadotropin-releasing hormone (GnRH) provides a non-surgical alternative. Both methods ultimately suppress sex hormone production, but their comparative effects on the gut microbiota, a crucial regulator of host health and metabolism, remain unclear. Here, 60 Sprague Dawley (SD) rats were randomly allocated into three groups—control (n = 20; 10 female and 10 male), surgical castration (n = 20; 10 female and 10 male), and GnRH immunocastration groups (n = 20; 10 female and 10 male)—at 4–5 weeks of age to comparatively investigate the impacts of surgical versus GnRH immunocastration on the gut microbiota. Our study demonstrated GnRH immunocastration significantly reduced gonadal weight, effectively suppressing gonadal development to a level comparable to surgical castration. However, the two methods induced distinct, sex-dependent shifts in the gut microbiota. Surgical castration reduced the gut microbial community diversity, whereas the community structure of GnRH immunocastrated rats more closely resembled that of the control group, indicating a milder impact on the microbial diversity and composition. Notably, GnRH immunocastration resulted in higher microbial alpha diversity than surgical castration in both female and male SD rats. Specific bacterial genera, such as Clostridia_UCG014, Lactobacillus, and Lachnospiraceae_UCG006, were similarly altered in both surgical castration and GnRH immunocastration female SD rats, while Intestinimonas and Erysipelatoclostridiaceae_UCG004 were concurrently changed in male SD rats. Conversely, Eubacterium_nodatum_group exhibited opposite responses, increasing with GnRH immunocastration but decreasing with surgical castration in male SD rats. Functional prediction revealed fundamental sex differences in microbial metabolic pathways. In females, nitrogen metabolism, glyoxylate/dicarboxylate metabolism, and mismatch repair were changed, while the pathways involved in siderophore biosynthesis, the citrate cycle (TCA cycle), genetic information processing, and amino acid metabolism were changed in male SD rats. In conclusion, GnRH immunocastration appears to be a less disruptive intervention, better preserving microbial diversity and inducing a unique functional profile. These findings highlighted the importance of considering the castration method’s impact on the gut microbial ecosystem in animal production and provided insights for developing humane and effective approaches to animal population control. Full article

This study involved 30 male pigs (DanBred × Duroc), which were divided into three groups of 10 animals each. Control group (C)—immunologically castrated boars with a slaughter weight of 120 kg; and experimental groups: E1—uncastrated boars with a slaughter weight of 120 kg, and E2—uncastrated boars with a slaughter weight of 105 kg. Animals from all groups were fed a complete feed mixture in a liquid form three times a day. After slaughter, their meat and backfat were analysed for the physicochemical parameters and for the contents of indole, skatole, androstenol, and androsterone. A higher protein content was determined in the meat of boars from group E1 (23.48%) compared to those from groups C (22.87%) and E2 (22.99%) (p ≤ 0.01), and a higher content of n-6 PUFAs in the meat of boars from group C (5.21 mg/g of meat) compared to those from group E2 (4.81 mg/g of meat) (p ≤ 0.05). Analysis of the chemical composition of backfat showed a lower protein level in the backfat of boars from group C (4.70%) compared to those from group E1 (6.20%) and a higher fat level in the backfat from boars from group C (70.09%) compared to those from groups E1 (65.90%) and E2 (64.75%) (p ≤ 0.05). Body weight and immunocastration status were also shown to affect the fatty acid profile. Immunocastration also reduced the content of androstenol and androsterone in meat and fat. A higher content of indole was demonstrated in the meat of boars from group C and in the backfat of those from group E2 compared to the animals from the other groups (p ≤ 0.001). Full article

Pork is a major source of animal protein worldwide, and its quality is influenced by pre- and post-slaughter procedures. Advances in molecular biology, particularly gene expression studies, support genetic improvement programs by enabling precise strategies to enhance meat quality and economic sustainability. This study evaluated meat quality traits and candidate gene expression in muscle and subcutaneous adipose tissue from different genetic lineages and sexes. A total of 120 pigs from three lineages—Line D (½ Duroc × ½ DB90), Line P (½ Pietrain × ½ DB90), and Line H (½ [Duroc and Pietrain] × ½ DB90); including immunocastrated males (IM) and females, were randomly selected. Meat quality was assessed using physicochemical parameters, and gene expression analysis was performed in 36 pigs using RT-qPCR with B2M, TBP, and RPL4 as references, and COL1A1, PRKAR2A, CAST, ADIPOQ, and PPARGC1A as targets. Lineage influenced drip loss and intramuscular fat, while lineage–sex interaction affected tenderness and color (L* and b*), and sex influenced b*. In muscle, sex affected COL1A1 and PRKAR2A, and lineage influenced COL1A1 and CAST. In adipose tissue, only CAST was lineage-dependent. Full article

Surgical castration of male piglets is a common practice to prevent boar taint and reduce aggressive behaviour. However, it raises welfare concerns and alters carcass fat deposition. Immunocastration, a vaccine-based alternative targeting gonadotropin-releasing hormone (GnRH), mitigates these welfare issues. This study evaluated carcass traits and meat quality in surgically and immunocastrated pigs slaughtered at two weight classes (approximately 116 kg and 136 kg). We compared growth performance, carcass composition, fat quality, and key meat quality indicators among surgically castrated males, immunocastrated males, and immunocastrated females. Inclusion of uncastrated and immunocastrated females provides novel comparative data for mixed-sex production systems, where such information is scarce. This broader evaluation helps fill current gaps in knowledge about immunocastration effects in female pigs. Surgically castrated males showed higher backfat thickness and fat content, particularly at the heavier weight, while immunocastrated pigs exhibited intermediate traits. Ultimate pH, colour, marbling, water-holding capacity, and moisture loss varied with castration method, sex, and slaughter weight, though many differences were subtle. The findings confirm that immunocastration offers a favourable balance between animal welfare and production traits, producing pork quality comparable to surgical castration. These results provide valuable insights for optimizing pork production systems, balancing welfare, efficiency, and meat quality. Full article

Objectives: Research on the immunocastration vaccine is of great significance for animal management. In this study, the gonadotropin-releasing hormone (GnRH) ferritin nanoparticle vaccine was constructed using Spy Catcher-Spy Tag (SC-ST) as a delivery system; Methods: The Spy Catcher was constructed to fuse with the expression vector pET-30a-SF of ferritin nanoparticles. Two polypeptides, STG1: Spy Tag-GnRH I-PADRE and STG2: Spy Tag-GnRH I-GnRH II, coupled to SF in vitro to form two nanoparticles, were designed and synthesized to detect castration effects in mice. We mixed them with the adjuvant MONTANIDE ISA 206 VG to explore the adjuvant’s effect on immunogenicity; Results: All immunized groups produced anti-GnRH specific antibodies after the second immunization, which was significantly higher in the immunized group and the combined adjuvant group than in the control group, and the immune response could still be detected at the 12th week. The concentrations of testosterone, follicle-stimulating hormone, and luteinizing hormone in serum were significantly decreased. The number of sperm in the epididymis of mice in each immune group was significantly reduced, and the rate of sperm deformity was high; Conclusions: The two ferritin-based GnRH nanoparticles developed in this study can significantly cause testicular atrophy, decreased gonadal hormone concentration, decreased sperm count, and increased deformity rate in male mice. These findings provide experimental evidence supporting their potential application in animal immunocastration. Full article

The objective of this study was to assess the effects of stocking density in the pen and lairage time before slaughter on blood stress indicators, skin lesions, and pork meat quality traits. A total of 1920 immunocastrated male pigs were shipped to a slaughterhouse. In order to maintain the proposed stocking densities, 72 pigs out of the 1920 animals were removed across loads from the experiment. The remaining 1848 pigs were randomly assigned to two different stocking densities in the lairage pen (0.42 m²/100 kg and 0.66 m²/100 kg) and two lairage times (2 h and 6 h). A total of 360 pigs were selected for the analysis of exsanguination blood glucose, creatine kinase, lactate dehydrogenase, cortisol concentration, hematocrit percentage, and carcass skin lesion scores, whereas meat quality was assessed in 240 loin muscles. Except for blood hematocrit percentage, the interaction stocking density × lairage pen had no effect on any parameter (p > 0.10). When compared to a lower stocking density (0.66 m²/100 kg), pigs kept at a higher stocking density (0.42 m²/100 kg) tended to present lower blood LDH concentrations (p = 0.06) and higher blood cortisol concentrations (p = 0.08) at slaughter and had greater carcass skin lesion scores (p < 0.001) and drier (lower drip loss) loin muscles (p = 0.04). Increased blood hematocrit percentage was found in pigs kept in lairage at a higher stocking density for 6 h when compared with the other lairage conditions (p < 0.01). Overall, stocking density, in particular when it was high, influenced more pigs’ stress conditions at slaughter and carcass and meat quality than the time spent in lairage. Full article

The growth of boars may be inhibited because of aggressive and/or sexual activity. Dietary Br, Mg and tryptophan (Trp) as well as immunocastration may reduce these behaviours. In Experiment 1, 200 boars and 40 barrows were allocated to six groups of four pens of 10 pigs per treatment. Control and immunocastrate (Improvac-vaccinated at 13 and 17 weeks, Imp) boars and barrows were fed a finisher ration while the others were fed diets supplemented with Mg (5 g Mg proteinate/kg), Br (140 mg NaBr/kg) and Trp (5 g Trp/kg). In experiment 2, 300 boars were stratified by weight and within three weight classes allocated to two pens of ten pigs per treatment. Control and Imp boars were fed a finisher ration while the other diets were supplemented with Br, Trp or both Br and Trp. In Experiment 1, average daily gain (ADG) was not affected by diet but the Imp boars had higher ADG than controls. Feed intake (FI) tended to be higher in all treatments compared to controls except for the Trp group. In Experiment 2, Imp boars had higher ADG and FI than other treatments while Br+Trp boars had higher ADG and FI than controls. These data suggest that immunocastration and dietary Trp and Br show promise for improving performance in group-housed boars. Full article

Immunization against Gonadotropin-Releasing Hormone (GnRH) has been successfully explored and developed for the parenteral inoculation of animals, aimed at controlling fertility, reducing male aggressiveness, and preventing boar taint. Although effective, these vaccines may cause adverse reactions at the injection site, including immunosuppression and inflammation, as well as the involvement of laborious and time-consuming procedures. Oral vaccines represent an advancement in antigen delivery technology in the vaccine industry. In this study, a Salmonella enterica serovar Typhimurium (S. Typhimurium) mutant lacking the pathogenicity island 2 (S. Typhimurium ΔSPI2) was used as a vehicle and mucosal adjuvant to deliver two genetic constructs in an attempt to develop an oral immunological preparation against gonadotropin hormone-releasing hormone (GnRH). S. Typhimurium ΔSPI2 was transformed to carry two plasmids containing a modified GnRH gene repeated in tandem (GnRXG/Q), one under eukaryotic expression control (pDNA::GnRXG/Q) and another under prokaryotic expression control (pJexpress::GnRXG/Q). A group of three male BALB/c mice were orally immunized and vaccination-boosted 30 days later. The oral administration of S. Typhimurium ΔSPI2 transformed with both plasmids was effective in producing antibodies against GnRXG/Q, leading to a decrease in serum testosterone levels and testicular tissue atrophy, evidenced by a reduction in the transverse tubular diameter of the seminiferous tubules and a decrease in the number of layers of the seminiferous epithelium in the testes of the inoculated mice. These results suggest that S. Typhimurium ΔSPI2 can be used as a safe and simple system to produce an oral formulation against GnRH and that Salmonella-mediated oral antigen delivery is a novel, yet effective, alternative to induce an immune response against GnRH in a murine model, warranting further research in other animal species. Full article

Pig producers in Europe adopt different production methods for male pig fattening. More than half of the animals are surgically castrated. The different interpretations of animal welfare in different countries lead to market differentiation and economically different production conditions, which do not restrict trade, but economically lead to drastic competitive changes for local producers. While the Netherlands has already implemented surgical castration for the export market, using CO₂ narcosis (NL), Denmark and Germany are each introducing their strategies with local anesthesia (DK) and isoflurane anesthesia (DE), respectively. Using typical pig farms from the agri benchmark Pig Network, the additional costs and economic impacts of animal welfare regulations are calculated. In Germany, isoflurane anesthesia increases costs by EUR 28.54 to EUR 49.86 per sow, or EUR 1.93 to EUR 3.81 per male piglet. This corresponds to a cost increase of around 5% per piglet. In Denmark, the costs of local anesthesia with procaine increase more moderately by EUR 3.55 to EUR 5.05 per sow, or around EUR 0.30 per male piglet. The cost increase here is less than 1% per piglet. The additional costs are leading to a loss of competitiveness for Denmark and Germany compared to the Netherlands. However, Germany is also losing profit significantly compared to Denmark. This study highlights that animal welfare regulations can negatively impact the competitiveness of the pig sector. It emphasizes the need for countries to implement such regulations carefully, ensuring that they do not lead to the loss of production or international competitiveness. A balanced approach that supports both animal welfare and economic sustainability is essential. Full article

Castration is a prevalent and indispensable practice in sheep husbandry, aiding in enhancing meat quality, mitigating aggressive behavior, and managing unwanted reproduction. Nevertheless, the conventional surgical castration procedure poses several challenges, including heightened stress and pain, detrimental impacts on animal welfare, and diminished economic efficacy in farming operations. Consequently, immunocastration methods, serving as substitutes for surgical castration, are progressively finding application in livestock. The rumen, an essential and distinctive digestive and absorptive organ in ruminants, has been associated with enhanced meat quality and productive performance following castration in previous research studies, albeit fewer investigations have explored the potential impacts of GnRH immunization on the rumen’s internal milieu in sheep post-de-escalation. Hence, the present study delved into evaluating the impact of GnRH immunocastration on the rumen microbiome and metabolomics in male Xizang sheep. This was achieved through the establishment of a GnRH immunocastration animal model and the collection of rumen fluid for microbiological and comprehensive metabolomics investigations. The outcomes of this investigation unveiled that the impact of GnRH immunocastration on body weight gain was more pronounced during the achievement of the castration objective. In addition, the Firmicutes-to-Bacteroidota ratio in the immune male (IM) group exceeded that of the control group (EM), suggesting that GnRH immunodeficiency may enhance the digestion and absorption of feed in male Xizang sheep. At the taxonomic level, the elevated presence of Prevotella and Quinella bacteria in the IM group compared to the EM group indicated that castration influenced a segment of the rumen microbiota in male Xizang sheep, thereby bolstering the digestive and metabolic efficacy of the rumen concerning nutrient utilization, particularly in the breakdown and absorption of proteins, carbohydrates, and lipids, ultimately expediting the fattening process and weight gain in male Xizang sheep following castration. Moreover, analysis of ruminal fluid metabolomics revealed that GnRH immunization had notable impacts on certain metabolites in the ruminal fluid of male Xizang sheep, with metabolites like 5-hydroxyindole acetic acid and 3-hydroxyindole acetic acid showing significant downregulation in the IM group compared to the EM group, while niacin and tyramine exhibited significant upregulation. These findings indicate a profound influence of GnRH immunization on the maintenance of ruminal equilibrium and ruminal health (including the health of ruminal epithelial cells). This study validates that GnRH immunocastration not only achieves the objectives of castration but also enhances ruminal health in male Xizang sheep, thus laying a foundational theoretical basis for the application and dissemination of GnRH immunocastration technology. Full article

Castration is often employed in animal management for reproductive control. However, it is important to evaluate its impact on animal welfare. In this study, we developed rat models for both surgical (n = 6) and GnRH immunocastration (n = 6) to assess the effects of these castration methods on physiological and behavioral characteristics. The novel GnRH-based vaccine significantly increased serum GnRH antibody levels and drastically reduced testosterone, with the testes shrinking to one-fifth the size of those in the control group, thereby halting spermatogenesis at the secondary spermatocyte stage. Behavioral evaluations demonstrated that sexual behavior was significantly suppressed in both surgically and immunologically castrated groups compared to the control, confirming the effectiveness of both methods. However, psychological tests revealed significant signs of depression and social deficits in the surgically castrated group, whereas the behavior of the GnRH-immunocastrated group did not significantly differ from the control. Furthermore, no significant differences in learning and memory were observed among the three groups in the water maze test. Compared to surgical castration, GnRH immunocastration offers effective results and better animal welfare, providing a more humane alternative for livestock management. Full article