Castrated Males Research Articles

Effect of gender (gilt and surgically and immunocastrated male) and ractopamine hydrochloride supplementation on growth performance, carcass, and pork quality characteristics of finishing pigs under commercial conditions1

This study evaluated the effects of gender and feeding of ractopamine on growth performance, carcass, and meat quality characteristics of pigs reared under commercial conditions. The study was performed as a randomized complete block design (blocking factor date of start on test) with a 3 × 2 factorial arrangement of treatments: 1) gender [gilt vs. surgical castrate vs. intact males immunocastrated] and 2) ractopamine level (0 vs. 5 g/ton). The study was conducted out over a fixed duration (126 d) from 1 wk after weaning (28 d of age; 8.04 ± 1.31 kg BW) to 154 d of age (111.44 ± 4.67 kg BW) in 3 growth periods: nursery (d 0 to 35 of the study), growing (d 35 to 70), and finishing (d 70 to 126). Ractopamine was fed for the final 28 d of the study (d 98 to 126). Pigs were kept in groups of 10 or 11 in the nursery phase and then moved to the growing-finishing facility where they were kept in groups of 22 to the end of the study. At the end of the growth study, pigs were harvested and carcass and pork quality were evaluated, including consumer evaluation of eating quality. During the nursery, there was no effect of gender (P > 0.05) on G:F, but surgical castrates grew faster (P < 0.05) than intact males and gilts and had greater (P < 0.05) ADFI than intact males. There was no effect of gender (P > 0.05) on ADG in the growing period; however, immunocastrated males had lower ADFI than surgical castrates and greater G:F than surgical castrates and gilts. In finishing, immunocastrated males and surgical castrates had similar ADG but grew faster than gilts; G:F was greater for immunocastrated males than the other genders. Feeding 5 compared to 0 g/ton ractopamine increased ADG and G:F but had no effect (P > 0.05) on carcass yield or fresh meat quality. Carcass yield was lower but percentage lean cut yield was greater for immunocastrated males than for surgical castrates. Longissimus muscle drip loss was greater (P = 0.05) for immunocastrated males than surgical castrates. Gender had no effect (P > 0.05) on consumer panel evaluation. Feeding ractopamine had no effect on pork flavor and tenderness but improved juiciness scores. Odor scores were similar (P > 0.05) for surgical castrates and immunocastrated males that were fed ractopamine. Consumers gave lower liking scores for odor for immunocastrated males than surgical castrates that were not fed ractopamine. This study highlights the feed efficiency and lean cut yield advantage for immunocastrated males compared to surgical castrates and suggests a similar growth response to feeding ractopamine in these genders. Although immunocastrated males had a lower carcass yield and higher drip loss, panelists were not able to detect differences in pork juiciness, flavor, and tenderness when compared to surgical castrate pigs.

Surgical castration of the male common hippopotamus (Hippopotamus amphibius)

In a prospective, clinical, surgery study we report here for the first time, in detail, on the surgical castration of 10 captive adult male common hippopotami (Hippopotamus amphibius). The successful procedures, a species-specific modification of standard equine castration techniques, provide valuable insight into the spatially dynamic nature of the common hippopotamus testis. The use of ultrasonography to locate the testis before and during the procedures and species-specific positioning during surgery greatly facilitated this distinctive procedure. Additionally, this surgical method provides an important additional tool for captive management of the common hippopotamus. Castration of individual males not only facilitates population control but can potentially also be employed to limit intermale aggression.

Gender Bias in Autoimmunity Is Influenced by Microbiota

Gender bias and the role of sex hormones in autoimmune diseases are well established. In specific pathogen-free nonobese diabetic (NOD) mice, females have 1.3-4.4 times higher incidence of type 1 diabetes (T1D). Germ-free (GF) mice lost the gender bias (female-to-male ratio 1.1-1.2). Gut microbiota differed in males and females, a trend reversed by male castration, confirming that androgens influence gut microbiota. Colonization of GF NOD mice with defined microbiota revealed that some, but not all, lineages overrepresented in male mice supported a gender bias in T1D. Although protection of males did not correlate with blood androgen concentration, hormone-supported expansion of selected microbial lineages may work as a positive-feedback mechanism contributing to the sexual dimorphism of autoimmune diseases. Gene-expression analysis suggested pathways involved in protection of males from T1D by microbiota. Our results favor a two-signal model of gender bias, in which hormones and microbes together trigger protective pathways.

Of mice and men‐warning: Intact versus castrated adult male mice as xenograft hosts are equivalent to hypogonadal versus abiraterone treated aging human males, respectively

Immune deficient male mice bearing human prostate cancer xenografts are used to evaluate therapeutic response to novel androgen ablation approaches and the results compared to surgical castration based upon assumption that testosterone microenvironment in intact and castrated adult male mice mimics eugonadal and castrated aging adult human males. To test these assumptions, serum total testosterone (TT) and free testosterone (FT) were determined longitudinally in groups (n > 20) of intact versus castrated adult male nude, NOG, and immune competent C57BL/6 mice. In adult male mice, TT and FT varies by 30- to 100-fold within the same animal providing a microenvironment that is only equivalent to hypogonadal, not eugonadal, adult human males (TT is 1.7 ± 1.2 ng/ml [5.8 ± 4.1 nM] in nude and 2.5 ± 1.3 ng/ml [8.7 ± 4.4 nM] in NOG mice versus >4.2 ng/ml [14.7 nM] in eugonadal humans). This was confirmed based upon enhanced growth of androgen dependent human prostate cancer xenografts inoculated into mice supplemented with exogenous testosterone to elevate and chronically maintain serum TT at a level (5 ng/ml [18 nM]) equivalent to a 50-year-old eugonadal human male. In castrated mice, TT and FT range from 2 to 20 pg/ml (7-70 pM) and <0.8 pg/ml (<2.6 pM), respectively, which is equivalent to castrate resistant prostate cancer (CRPC) patients treated with abiraterone. This was confirmed based upon the inability of another CYP17A1 inhibitor, ketoconazole, to inhibit the growth of CRPC xenografts in castrated mice. Adult male mice supplemented with testosterone mimic eugonadal human males, while unsupplemented animals mimic standard androgen ablation and castrated animals mimic abiraterone treated patients. These studies confirm what is claimed in Robert Burns' poem "To a Mouse" that "The best laid schemes of mice and men/often go awry.".

Effect of energy concentration on growth performance and carcass quality of Iberian pigs reared under intensive conditions

In total, 192 Iberian pigs were used to investigate the effects of net energy (NE) concentration of the diet on growth performance and carcass quality of castrated females (CF) and castrated males (CM). From 30 to 112 kg body weight (BW), three diets were formulated with similar digestible amino acid content per kcal of NE but differing in energy concentration (2,045, 2,175 and 2,305 kcal NE kg-1 from 30 to 81 kg BW and 2,175, 2,305 and 2,445 kcal NE kg-1 from 81 to 112 kg BW). From 112 kg to slaughter (148 kg BW), all pigs received a common finisher diet. Each treatment was replicated eight times and the experimental unit was a pen with four pigs. A decrease in NE concentration of the diet increased feed intake (p&lt;0.05) and tended to impaired feed conversion ratio (p&lt;0.10), whereas carcass and meat quality traits were not affected. Castrated males ate more feed and grew faster but had less fat thickness at the gluteus medius muscle than CF (p&lt;0.05). However, no differences in carcass and meat quality traits between genders were detected. We conclude that a reduction in NE content of the grower diets did not affect growth rate and therefore, it not a valuable alternative to avoid excess of BW at slaughter in Iberian pigs reared under intensive management conditions. Also, both genders can be used for the production of high quality carcasses destined to the dry-cured industry.

Diversidade genética e estrutura populacional de subpopulações remanescentes da raça equina nordestino

O presente trabalho teve como objetivo avaliar a estrutura e diversidade genética de quatro subpopulações do cavalo Nordestino utilizando 14 marcadores microssatélites. Amostras de bulbo capilar de 393 cavalos foram coletadas, distribuídos em: 61 animais do vale do Salitre (JUAZ-BA) localizado no estado da Bahia, 89 das mesorregiões Norte e Centro-Norte do estado do Piauí, 58 animais da cidade de Agrestina (AGRE-PE) e 185 das mesorregiões Sertão e Sertão do São Francisco localizado no estado de Pernambuco (SERT-PE). A diversidade genética, diferenciação genética e efeito de gargalo genético foram avaliados nas 4 subpopulações do cavalo Nordestino. Observou-se elevada diversidade genética e valores de Fis que não evidenciaram níveis de consanguinidade significativa, prova-velmente isso se deve à acasalamentos entre as subpopulações. Efeito de gargalo genético recente não foi detectado para as quatro subpopulações, porém os modelos IAM e TPM sugeriram um efeito de gargalo genético não recente. Isso pode ser reflexo da redução no número de reprodutores decorrente da castração de machos, processo de mecanização e mudanças no estilo de vida das populações da zona rural. Eventos mais antigos do efeito de gargalo genético não foram suficientes para evidenciar uma diferenciação genética entre as 4 subpopulações, portanto elas formam um só grupo genético.

Protective role of testosterone in ischemia-reperfusion-induced acute kidney injury

Men are at greater risk for renal injury and dysfunction after acute ischemia-reperfusion (I/R) than are women. Studies in animals suggest that the reason for the sex difference in renal injury and dysfunction after I/R is the protective effect of estrogens in females. However, a reduction in testosterone in men is thought to play an important role in mediating cardiovascular and renal disease, in general. In the present study, we tested the hypothesis that I/R of the kidney reduces serum testosterone, and that contributes to renal dysfunction and injury. Male rats that were subjected to renal ischemia of 40 min followed by reperfusion had a 90% reduction in serum testosterone by 3 h after reperfusion that remained at 24 h. Acute infusion of testosterone 3 h after reperfusion attenuated the increase in plasma creatinine and urinary kidney injury molecule-1 (KIM-1) at 24 h, prevented the reduction in outer medullary blood flow, and attenuated the increase in intrarenal TNF-α and the decrease in intrarenal VEGF at 48 h. Castration of males caused greater increases in plasma creatinine and KIM-1 at 24 h than in intact males with renal I/R, and treatment with anastrozole, an aromatase inhibitor, plus testosterone almost normalized plasma creatinine and KIM-1 in rats with renal I/R. These data show that renal I/R is associated with sustained reductions in testosterone, that testosterone repletion protects the kidney, whereas castration promotes renal dysfunction and injury, and that the testosterone-mediated protection is not conferred by conversion to estradiol.

Ontogeny of pronounced female-biased sexual size dimorphism in the Malaysian cat gecko (Aeluroscalabotes felinus: Squamata: Eublepharidae): A test of the role of testosterone in growth regulation

Species differences in the effect of male gonadal androgens on male growth are considered a possible mechanism allowing shifts in magnitude and even direction of sexual size dimorphism (SSD) in squamate reptiles. According to the bipotential growth regulation hypothesis, the androgen testosterone (T) enhances male growth in species with male-biased SSD and conversely inhibits male growth in males of female-larger species. In the present study, we describe the ontogeny of the pronounced female-biased SSD and report the effect of T on growth via hormonal manipulations in males and females of the Malaysian cat gecko (Aeluroscalabotes felinus). In accord with the predictions of the bipotential growth regulation hypothesis, growth was inhibited by replacement of T in castrated males. Additionally, exogenous T inhibited growth of females to male-typical levels. Nevertheless, male castration alone did not significantly affect growth, contrary to the prediction of the bipotential growth regulation hypothesis, which contradicts the generality of this hypothesis. Application of exogenous T to females can interfere with normal ovarian function. Therefore, although not directly tested in this study, we suggest that ovarian effects on the ontogeny of SSD in A. felinus are consistent with our results. The development of SSD is a function of differential growth between the sexes, and potential sex-specific growth regulation in both males and females should be taken into account as possible proximate mechanisms responsible for SSD.

Dietary inulin alters the intestinal absorptive and barrier function of piglet intestine after weaning

An experiment was conducted to study the effects of dietary inulin supplementation on the electrophysiological properties of small intestine of suckling and weaned piglets as indicators for glucose absorption and barrier function. Ten sows were divided into two groups, receiving either a control diet, or a diet with 3% inulin. The diets were fed from 3weeks ante partum to 6weeks post partum. In the first 2weeks of life, piglets received only sow’s milk. Irrespective to sex and without castration of males, four piglets (one piglet of each litter) from each group were selected and sacrificed on day 10 of age. The gastrointestinal tract of each piglet was removed and segments were immediately taken from the mid-jejunum and mounted in Ussing chambers. Furthermore, at weaning (6weeks old) 8 piglets were randomly selected irrespective to sex and males were un-castrated (4 animals from sows received control diet and 4 animals from sows received 3% inulin supplemented diet) and fed for 2weeks either control weaning diet or inulin supplemented diet. Thereafter segments of the mid-jejunum were used to investigate the effect of inulin on the gut electrophysiology of weaned piglets. The increase in short-circuit current (Isc) after the addition of glucose is an indicator of higher glucose absorption and the higher tissue conductance (Gt) of the epithelium suggested a higher intestinal permeability to paracellular Na+. In suckling piglets, the addition of d-glucose on the luminal side of the isolated jejunal mucosa increased (P<0.001) the Isc in the inulin-supplemented and control groups compared to basal values. Electrogenic glucose transport (ΔIsc) was similar in suckling piglets from sows fed inulin or control diet, suggesting that feeding of inulin to the mother sows had no effect on glucose absorption across the jejunal mucosa of suckling piglets. However, the dietary inulin supplementation after weaning increased the ΔIsc (P<0.001) compared with the controls, suggesting that the inulin supplementation increased the electrogenic transport of glucose across the jejunal mucosa of weaned piglets indicating higher glucose absorption. Furthermore, the Gt was higher in the inulin-supplemented weaned piglets than in control piglets, which could be due to the increased paracellular permeability to Na+. In conclusion, dietary inulin increased the glucose transport and altered the intestinal barrier by increasing the intestinal permeability in the jejunal mucosa of post-weaned piglets. Furthermore, the results indicated that inulin has a positive effect on glucose absorption in the piglet small intestine after weaning and subsequently the dietary inulin offers a promising approach to avoid post-weaning gastrointestinal tract disorders in pigs.

Attenuation of Corpus Callosum Axon Myelination and Remyelination in the Absence of Circulating Sex Hormones

Sex differences in the structure and organization of the corpus callosum (CC) can be attributed to genetic, hormonal or environmental effects, or a combination of these factors. To address the role of gonadal hormones on axon myelination, functional axon conduction and immunohistochemistry analysis of the CC in intact, gonadectomized and hormone-replaced gonadectomized animals were used. These groups were subjected to cuprizone diet-induced demyelination followed by remyelination. The myelinated component of callosal compound action potential was significantly decreased in ovariectomized and castrated animals under normal myelinating condition. Compared to gonadally intact cohorts, both gonadectomized groups displayed more severe demyelination and inhibited remyelination. Castration in males was more deleterious than ovariectomy in females. Callosal conduction in estradiol-supplemented ovariectomized females was significantly increased during normal myelination, less attenuated during demyelination, and increased beyond placebo-treated ovariectomized or intact female levels during remyelination. In castrated males, the non-aromatizing steroid dihydrotestosterone was less efficient than testosterone and estradiol in restoring normal myelination/axon conduction and remyelination to levels of intact males. Furthermore, in both sexes, estradiol supplementation in gonadectomized groups increased the number of oligodendrocytes. These studies suggest an essential role of estradiol to promote efficient CC myelination and axon conduction in both sexes.

Review on the consequences of using Improvac TM in modern pig production

In Europe growing concerns regarding animal welfare issues in pig production have forced the pig industry to introduce alternative methods to conventional castration procedures. Besides the raising of entire males and castration in combination with analgesia and anaesthesia the vaccination against GnRF (Gonadotropin-releasing factor) seems to be the most promising long-term solution. Immunised male pigs (IM) show higher average daily weight gain than surgically castrated males (CM). Additionally the feed intake in IM is lower than in CM and feed conversion ratio is consequently better. Carcass weight, back fat depth and dressing percentage of IM pigs are intermediate between CM and entire males while meat quality seems not to be influenced by castration technique since CM and IM show comparable results. Steroid hormone concentrations in IM decline to very low levels (below detection line) after the second administration of the anti-GnRF vaccine and boar taint compounds are reliably metabolized. Pigs which received two injections of the anti-GnRF vaccine reduce their sexual and aggressive behaviour to levels of CM pigs which results in low incidents of injury and carcass damages. Surveys analyzing the consumers’ attitude to vaccination against boar taint reveal that if profound information on the technique is provided, the acceptance of meat from vaccinated animals is even better than the acceptance of meat from pigs castrated under current farm conditions. Furthermore economic analyses reveal that immunisation against GnRF provides a potential for a return on investment since better feed efficiency compensates for the additional costs of drug and labour time.

Persistent efficacy and production benefits following use of extended-release injectable eprinomectin in grazing beef cattle under field conditions

Seven studies were conducted in commercial grazing operations to confirm anthelmintic efficacy, assess acceptability, and measure the productivity response of cattle to treatment with eprinomectin in an extended-release injectable formulation (ERI) when exposed to nematode infected pastures for 120 days. The studies were conducted under one protocol in the USA in seven locations (Arkansas, Idaho, Louisiana, Minnesota, Missouri, Oregon, and Wisconsin). Each study had 67–68 naturally infected animals for a total of 475 (226 female, 249 male castrate) Angus or beef-cross cattle. The animals weighed 133–335kg prior to treatment and were approximately 3–12 months of age. The studies were conducted under a randomized block design based on pre-treatment body weights to sequentially form 17 replicates of four animals each within sex in each study. Animals within a replicate were randomly assigned to treatments, one to Eprinomectin ERI vehicle (control) and three to Eprinomectin ERI (5%, w/v eprinomectin). Treatments were administered at 1mL/50kg body weight once subcutaneously anterior to the shoulder. All animals in each study grazed one pasture throughout the observation period of 120 days. Cattle were weighed and fecal samples collected pre-treatment and on 28, 56, 84, and 120 days after treatment for fecal egg and lungworm larval counts. Positive fecal samples generally were cultured en masse to determine the nematode genera attributable to the gastrointestinal helminth infection. Bunostomum, Cooperia, Haemonchus, Nematodirus, Oesophagostomum, Ostertagia, and Trichostrongylus, when present, were referred to as strongylids. At all post-treatment sampling intervals, Eprinomectin ERI-treated cattle had significantly (P<0.05) lower strongylid egg counts than vehicle-treated controls, with ≥95% reduction after 120 days of grazing. Over this same period, Eprinomectin ERI-treated cattle gained more weight (43.9lb/head) than vehicle-treated controls in all studies. This weight gain advantage was significant (P<0.05) in six of the studies with the Eprinomectin ERI-treated cattle gaining an average of 42.8% and the control cattle gaining 33.1% of their initial weight. No adverse reactions were observed in the treated animals.

Effects of tail docking and castration on stress responses in lambs and the influence of prenatal glucocorticoid treatment

It is common practice in Australian agriculture to remove the tails of lambs to prevent infection and to castrate males to prevent behavioural problems and unwanted reproduction. We have studied the pain and stress responses to these interventions by measuring changes in the hypothalamic-pituitary-adrenal (HPA) axis and β-endorphin levels. Further, we have evaluated the effects of prenatal exposure to dexamethasone, which is known to affect the developing HPA axis. In control animals that had received prenatal saline treatment, plasma cortisol and adrenocorticotrophin (ACTH) levels increased after the interventions in both females and males. Plasma β-endorphin levels also increased after the interventions, but the responses were less consistent. Prenatal dexamethasone exposure early in pregnancy (dexamethasone 0.14 mg kg(-1) ewe weight injection commenced on day 40 of pregnancy for four consecutive intramuscular injections at 12-hourly intervals) blunted the cortisol response to tail docking in female offspring, but not to combined tail docking and castration in males. It had no effect on ACTH or β-endorphin responses in either sex. These findings describe the stress responses to these common agricultural interventions and suggest that long-term development of the HPA axis in females is altered by prenatal exposure to dexamethasone.

Gender Differences in the Anatomy of the Perineal Glands in Guinea Pigs and the Effect of Castration

Perineal glands in guinea pigs are part of the sebaceous glandular complex. Their secretions are used for scent marking. This is important for social status and can be seen in both sexes and castrated males. Discrepancy exits about the existence of these glands in female guinea pigs and knowledge of the anatomical consequences of castration on the male perineal glands is sparse. To examine these uncertainties related to gender, perineal glands from 13 sexually mature pet guinea pigs were examined macro- and microscopically. Clear gender differences in the anatomy of perineal glands were found, and castrated males showed signs of atrophy and fatty infiltration in the glands. Females do have perineal glands, although smaller than the glands in the male. The glands are typically sebaceous with multiple excretory ducts. A macroscopic unique feature in the males was the clearly evident orifices of a large excretory duct on each side of the slightly everted perineal sac. However, the reason for this gender difference is not clear. In castrated males, the orifices were atrophied and difficult to see. In addition, the sebaceous glands of the hair follicles in the skin folds of the perineal opening were smaller and less abundant in females and castrated males. The changes in castrated males are presumably linked to the hormonal changes and decreased secretion after castration. The dense keratin layer in the perineal sac was thicker in males than in both castrated males and females and could contribute to the concrement formation seen mainly in males.

Oestrogen attenuates tumour progression in hepatocellular carcinoma

The precise mechanisms underlying gender disparity in hepatocellular carcinoma (HCC) progression and prognosis are not understood. We demonstrate that oestrogen attenuates HCC progression in vitro and in vivo, and this may contribute to the gender differences in HCC behaviour. To investigate the role of oestrogen in HCC progression, we developed an orthotopic homograft tumour model by liver implantation of H22 cells. In combination with male castration, female ovariectomy, and oestrogen treatment, we tested the hypothesis that oestrogen contributes to gender disparity in this model. Pathological analyses were performed to examine the changes in biological behaviour of liver cancer cells, and two cell lines were used to investigate possible molecular mechanisms of the suppressive effect of oestrogen. Our data showed that oestrogen modulates HCC malignancy in vivo by reducing tumour cell invasion, arresting cell cycle progression, and promoting apoptosis, characterized by decreased expression of MMP-2, MMP-9, PCNA, cyclin A, cyclin D1, and Bcl-2, and increased expression in cleaved caspase 3. Through in vitro assays, we further confirmed the changes in expression levels of these related proteins, gained insights into the molecular cascades of oestrogen-induced HCC suppression, and indicated the oestrogen receptor α-mediated inhibition of NF-κB binding activity as a pivotal event in this process. This study represents a novel description of the mechanisms regarding the suppressive effects of oestrogen on HCC, adding a new understanding to the gender disparity in HCC progression. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

‘Making the World Weep’? Decapitation/Castration in Puccini’s Turandot

Drawing upon Freudian psychoanalysis, in this article I argue that decapitation in Puccini’s Turandot — that is, the beheading of Turandot’s suitors — functions as an enactment of the male castration complex. As such, it is the site upon which fears of castration on the part of Puccini and the patriarchal society to which he belonged are played out. The opera illuminates the composer’s latent misogyny — a misogyny which permeated a substantial proportion of the national psyche during the early twentieth century in Italy, as well as many men’s attitudes towards women during this period which saw the aftermath of the rise of the movement for female emancipation. I begin by discussing the theme of decapitation in the opera before examining the archetypal suffering heroine in Puccini’s oeuvre. I then focus on a secondary character from the opera, Liù, Puccini’s partial addition to the dramaturgy: Liù is made to suffer for approximately fourteen minutes during the final act, after which, somewhat sadistically, she is made to commit suicide. Following recent work by feminist musicologist Carolyn Abbate and philosopher Adriana Cavarero, I argue that Liù’s ‘undoing’ in the dramaturgy is surpassed by the ‘envoicing’ of the diva — the female performer — singing her role.

Influence of immunisation against GnRF on agonistic and mounting behaviour, serum testosterone concentration and body weight in male pigs compared with boars and barrows

The aim of the present study was to assess the effects of vaccination against boar taint on testosterone levels, body weight and behaviour in male fattening pigs when compared with boars and barrows. The study was carried out in two replicates over time. Pigs were allocated to fattening pens according to treatment group (immunised males (IM), castrated males (CM), entire males (EM)) with 10 and 13 pigs per pen in batches one and two, respectively. IM pigs were vaccinated twice with Improvac™ according to manufacturer's instructions (first injection was given on the day of entry to the fattening unit, second injection was performed when pigs had an average weight of 76.6kg and 80.4kg in the two replicates over time, respectively). During fattening, pigs were videotaped twice (test periods one and two) for a consecutive period of 96h during each test period and blood samples were taken. Live weight measurements were conducted on a weekly basis. Before second vaccination was given (test period one), IM pigs had serum testosterone levels comparable to those of entire boars. Two weeks after second Improvac™-injection (test period two) testosterone levels of IM pigs decreased significantly (p<0.05). Agonistic as well as mounting behaviour of IM pigs was comparable to the behaviour of EM pigs during test period one. Two weeks after second Improvac™-injection fight time as well as fight duration decreased significantly (p<0.05) in the Improvac™-treated group to levels comparable to those of CM pigs, whereas both parameters remained on high levels in EM pigs. The number of fights, however, appeared not to be affected by vaccination with Improvac™, as IM and EM pigs revealed higher numbers than CM pigs during both test periods. IM and EM pigs showed comparable numbers of mountings as well as mounting time and mounting duration during test period one. Second Improvac™-injection was followed by a significant decrease in all three parameters in IM pigs (p<0.05). When compared with the other treatment groups CM pigs performed least agonistic and mounting behaviour during both test periods. IM and EM pigs performed significantly more manipulatory behaviour than CM pigs before second Improvac™-injection is given. During test period two EM showed more manipulatory behaviour than CM pigs with IM pigs in between. From our results we conclude that immunisation against 49 GnRH has the potential to reduce agonistic as well as mounting behaviour in male fattening pigs to very low levels which may result in improved animal welfare when compared with fattening of entire boars.

Expression of Na+-D-glucose cotransporter SGLT2 in rodents is kidney-specific and exhibits sex and species differences.

With a novel antibody against the rat Na(+)-D-glucose cotransporter SGLT2 (rSGLT2-Ab), which does not cross-react with rSGLT1 or rSGLT3, the ∼75-kDa rSGLT2 protein was localized to the brush-border membrane (BBM) of the renal proximal tubule S1 and S2 segments (S1 > S2) with female-dominant expression in adult rats, whereas rSglt2 mRNA expression was similar in both sexes. Castration of adult males increased the abundance of rSGLT2 protein; this increase was further enhanced by estradiol and prevented by testosterone treatment. In the renal BBM vesicles, the rSGLT1-independent uptake of [(14)C]-α-methyl-D-glucopyranoside was similar in females and males, suggesting functional contribution of another Na(+)-D-glucose cotransporter to glucose reabsorption. Since immunoreactivity of rSGLT2-Ab could not be detected with certainty in rat extrarenal organs, the SGLT2 protein was immunocharacterized with the same antibody in wild-type (WT) mice, with SGLT2-deficient (Sglt2 knockout) mice as negative control. In WT mice, renal localization of mSGLT2 protein was similar to that in rats, whereas in extrarenal organs neither mSGLT2 protein nor mSglt2 mRNA expression was detected. At variance to the findings in rats, the abundance of mSGLT2 protein in the mouse kidneys was male dominant, whereas the expression of mSglt2 mRNA was female dominant. Our results indicate that in rodents the expression of SGLT2 is kidney-specific and point to distinct sex and species differences in SGLT2 protein expression that cannot be explained by differences in mRNA.

A comparison of slaughter performance and meat quality of pigs immunised with a gonadotrophin-releasing factor vaccine against boar taint with physically castrated pigs

The objective of this study was to evaluate the effect of vaccination against gonadotropin-releasing factor (GnRF) on carcass characteristics and meat quality and back fat quality. In total, 400 healthy male pigs were randomly assigned into two treatment groups: physically castrated males (CM) and vaccinated males (IM). CM pigs were physically castrated within 3 days of age. IM pigs received the GnRF vaccine twice, at 14 and 21 weeks of age. At the end of the experiment, 20 pigs of each treatment were weighed individually and slaughtered at 25 weeks of age. The longissimus muscle was collected to evaluate the meat quality including pH, drip loss, shear force, cooking loss, intramuscular fat, fatty acid composition and inosine monophosphate. Subcutaneous fat was sampled to evaluate fatty acid composition. IM pigs had a lower dressing percentage and were leaner (P &lt; 0.01). The inosine monophosphate content was higher in pork from IM pigs than from CM pigs (P &lt; 0.05). IM pigs had a higher content of polyunsaturated fatty acids in longissimus muscles than CM pigs (P &lt; 0.01), mostly because of the higher linoleic acid content (P &lt; 0.01). IM pigs had higher levels of unsaturated fatty acids in subcutaneous fat than CM pigs (P &lt; 0.01), mostly because of the higher linoleic acid and linolenic acid (P &lt; 0.01) and the lower myristic acid content (P &lt; 0.01). There were no adverse effects of the GnRF vaccine on slaughter performance and meat quality of pigs. These results suggest that GnRF vaccine administered to pigs increases the inosine monophosphate content in longissimus muscles and the content of polyunsaturated fatty acids in longissimus muscles and back fat. Consequently, vaccination with Improvac for boar taint control will provide a good alternative to physical castration of male pigs.

Damara sheep have higher digestible energy intake than Merino sheep when fed low-quality or high-quality feed

The use of animals that are resilient to challenging environments is becoming of increasing importance in animal production systems. Interest in breeds of sheep such as the Damara for sheep meat production is increasing in Australia. Anecdotally this breed outperforms the traditionally grazed Merino in the harsh rangeland environments encountered in the Pastoral Zone of Australia, but little evidence is available to support this claim. A trial was conducted to quantify differences in the efficiency of feed utilisation and growth performance of Damara and Merino sheep under two contrasting dietary regimes. Eighteen castrate males of each breed were offered a ‘low-quality’ diet (L) (7 MJ/kg ME; 8% crude protein, as per manufacturer’s analysis) followed by a ‘high-quality’ diet (H) (11 MJ/kg dry matter and 16% crude protein, as per manufacturer’s analysis). On the L diet, Damaras had similar ad libitum feed intake as Merinos, but the digestibility of feed dry matter and energy was ~10% higher in Damaras than Merinos. Damaras also gained weight (38 g/day) on the L diet, while Merinos lost weight (28 g/day) (P &lt; 0.002). On the H diet the Damaras consumed 14% more feed (P &lt; 0.053) and grew 30% faster than Merinos (P &lt; 0.002), but there was no difference in the apparent dry matter or energy digestibility of the feed. At the conclusion of the trial the Damara carcasses were 22% heavier (28.1 versus 23.1 kg), and had higher dressing percentages (53.2 versus 41.5%) than Merinos, but the proportions of carcass components did not differ. The Damaras achieved higher total digestible energy intakes than the Merinos on both diets. On the low-quality feed this was achieved through higher feed digestibility and on the high-quality feed through greater voluntary feed intake. We speculate that this arises from variation between the breeds in rumen volume, particle flow and the site of digestion, but further studies are required to confirm this contention. The ability of Damara sheep to obtain more nutrients from widely differing feed bases makes them an attractive alternative sheep breed for sheep meat production. Furthermore, the presence of such variation between genotypes offers potential for selective breeding and development of commercial lines of sheep.