Plasma leptin, feed intake and body fat accumulation in fattening castrated male and female lambs

The main objective of this study was to investigate the relationships between changes in plasma leptin concentration and feed intake or bodyweight in female and castrated male lambs with fattening. Four female and four castrated male lambs were used and were fed roughage and concentrate supplemented with beef tallow ad libitum for 28 weeks. Although the feed intake and bodyweight increased with fattening in both the castrated male and female lambs, they decreased at 24–28 weeks in the female lambs. At the end of fattening, the crude fat content in the muscle (loin) of the female lambs was significantly higher than in the castrated male lambs (P < 0.05), while the crude protein content in the loin and fillet meat was higher in the castrated male than in the female lambs (P < 0.05). The plasma leptin concentration showed high values at a later stage of fattening (P < 0.05). In the female lambs the plasma insulin concentration increased at a later stage of fattening (P < 0.05) and was positively correlated (P < 0.0001, r = 0.78) with plasma leptin. Plasma metabolites (glucose, nonesterified fatty acid, total cholesterol and triglyceride) concentrations were also changed with fattening. Plasma total cholesterol was positively related to plasma leptin, more closely in the female than in the castrated male lambs (in females, r = 0.63, P < 0.001; in males, r = 0.38, P < 0.01). The accumulation of body fat was probably accelerated by the consumption of a lot of concentrate feed supplemented with treated beef tallow and by the stimulation of insulin with fattening. Consequently, the plasma leptin concentration increased, especially toward the end of the fattening period. The decrease in feed intake and bodyweight after the 24th week of fattening was possibly caused by an increase in leptin that is involved in the homeostatic regulation of body energy by regulating appetite.     

Sulfamethazine residues in swine: comparison of on-farm monitoring methods

Three sulfamethazine-residue detection methods were used to evaluate samples collected from five swine farms over a 12-month period. All cooperating farms included sulfamethazine in swine diets at various stages of production, for growth promotion or disease control, and followed recommended drug withdrawal periods. Swine finishing ration, swine urine, and swine serum from market-weight animals were tested monthly for the presence of sulfamethazine. Thin-layer chromatograph (TLC) analysis of swine urine was the gold standard by which three other test method-sample combinations were compared. Samples were analyzed for sulfamethazine using TLC (feed), competitive enzyme immunoassay (serum), and agar-diffusion swab test (urine). The relative sensitivities and specificities of sulfamethazine-residue detection for the three combinations were: (1) TLC analysis (27%, 94%); (2) competitive enzyme immunoassay analysis (58%, 59%); (3) agar-diffusion swab test (78%, 12%). None of the three methods tested was individually adequate for on-farm monitoring of sulfonamide residues. Sulfamethazine residues in swine urine were found on 43.3% of the monthly farm visits and in 19.7% of all swine tested.     

Sulfamethazine residues in swine

Two possible causes of violative sulfonamide residues in swine were studied. To determine if sulfamethazine accumulated in the tissues of swine when the drug was administered in feed, the rates of plasma drug disappearance following a single oral dose and continuous feeding of the drug were compared. The rate of plasma drug disappearance was not significantly different (α= 0.05) when the two methods of drug dosing were compared. When feed containing 2 μg sulfamethazine/gm was fed to swine during a 7—day period preceding slaughter, the animal's liver contained violative residues. Violative concentrations of sulfamethazine were detected in the livers, kidneys, and skeletal muscle of swine which consumed feed containing 8 μg sulfamethazine/gm.     

Characterization of anti‐Müllerian hormone in a case of bovine male pseudohermaphroditism

The current report aimed to characterize plasma anti‐Müllerian hormone (AMH) in bovine male pseudohermaphroditism. The blood AMH concentration in a Japanese Black male pseudohermaphrodite calf was compared with pre‐ and post‐pubertal male and female calves and castrated calves. The concentration in the case was higher than in post‐pubertal males, castrated males, and pre‐ and post‐pubertal female calves (p < .05), but similar to that in pre‐pubertal male calves. After extraction of the testes, the concentration in the case dropped to a certain extent. The extracted testes expressed AMH, as detected by immunohistochemistry. This study is the first to show the characterization of AMH in a male pseudohermaphrodite calf. AMH levels in peripheral blood might be useful to diagnose male pseudohermaphroditism in cattle.     

Testosterone increases urinary free felinine, N-acetylfelinine and methylbutanolglutathione excretion in cats (Felis catus)

Two days after castration, urinary free felinine plus N-acetylfelinine decreased 24% in male cats, but, by day 5, the concentration had not decreased to that routinely found in males that have been castrated for several months. In a second experiment, three groups of castrated adult male cats received different subcutaneous injections: control (carrier), testosterone, testosterone plus estradiol. A fourth group of intact adult female cats received a testosterone injection. Urine was collected and analysed for free felinine, N-acetylfelinine and 3-methylbutanolglutathione. Baseline blood testosterone and estradiol concentrations were low during the pre-period, but increased sharply after hormone injections. The concentration of all three urinary metabolites increased as a result of testosterone injections with estradiol not modulating the effect. The effect of testosterone was not gender dependent. The concentration of free felinine, N-acetylfelinine and 3-methylbutanolglutathione in the urine remained low in the placebo control group throughout the study. The relative molar contribution of free felinine to the total amount of felinine containing compounds increased due to testosterone treatment, while the contribution of 3-methylbutanolglutathione and N-acetylfelinine decreased. Testosterone increases free felinine, N-acetylfelinine and 3-methylbutanolglutathione excretion in castrated adult male and intact female cats, whereas estradiol does not modulate this effect.     

Pharmacokinetics and renal clearance of sulfamethazine, sulfamerazine, and sulfadiazine and their N4-acetyl and hydroxy metabolites in horses

Plasma disposition, protein binding, urinary recovery, and renal clearance of sulfamethazine (SMZ), sulfamerazine (SMR), and sulfadiazine (SDZ) and their N4-acetyl and hydroxy derivatives were studied in 4 horses in a crossover trial. The plasma concentration-time curves of the metabolites paralleled those of the parent drug in the elimination phase. Sulfamethazine and SMR were extensively metabolized. In plasma and urine, the main metabolite of the 3 sulfonamides tested was the 5-hydroxypyrimidine derivative, which was highly glucuronidated. Difference in elimination half-life of SMZ, SMR, and SDZ could be related to difference in metabolism and renal clearance values. Metabolism speeds drug elimination, producing compounds with higher renal clearance values than those of the parent drug. Methyl substitution in the pyrimidine side chain increased hydroxylation of the parent drug, but prolonged the persistence of the sulfonamides studied in the body. The high concentration of N4-acetyl and hydroxy metabolites of SMZ and SMR in plasma and urine decreased the potential antibacterial activity of the parent drugs. Sulfadiazine was less metabolized, and microbiologically determined SDZ concentrations in plasma and urine were slightly lower than those measured by high-performance liquid chromatography.     

Comparative aspects and sex differentiation of plasma sulfamethazine elimination and metabolite formation in rats, rabbits, dwarf goats, and cattle.

Plasma disposition and urinary recovery of sulfamethazine (SMZ), its N4-acetylated metabolite (N4AcSMZ), and 2 of its hydroxylated metabolites--5-hydroxysulfamethazine (5OHSMZ) and 6-hydroxymethylsulfamethazine (6CH2OHSMZ)--were determined in either sex of 4 animal species: rats, dwarf goats, rabbits, and cattle. Rats, rabbits, and dwarf goats had significant (P < 0.01) sex difference in SMZ plasma clearance. Male rats had higher plasma clearance than did female rats, and excreted higher amounts of the hydroxy metabolites and lower amounts of N4AcSMZ. The N4AcSMZ metabolite was predominant in plasma and urine of rabbits. Male rabbits had higher plasma clearance than did female rabbits, but differences in metabolite profile were not apparent. With regard to plasma SMZ elimination, the situation in goats was opposite to that in rats. Male goats had considerably lower clearance than did female goats. This was associated with a lower hydroxylation rat in males. Plasma half-life of SMZ in cows was lower than that in bulls, probably because of a smaller distribution volume in cows. Compared with elimination via urine, elimination via milk was negligible in cows. Significant differences in metabolite profiles were not found between bulls and cows. Similar to those in rats and mice, hormone-dependent xenobiotic metabolic pathways may exist in other species. Depending on species and xenobiotic compound residue concentrations of xenobiotics, their metabolites, or both may differ with sex of the animal, or may be altered after treatment with anabolic hormones.     

Hormonal regulation of oxidative drug metabolism in the dwarf goat. The effect of sex and hormonal treatment on plasma disposition and metabolite formation of sulphadimidine

Sulphadimidine (20 mg/kg i.v.) plasma elimination and metabolite formation were studied in intact male, castrated male, and female dwarf goats. Plasma pharmacokinetics and urinary metabolite patterns were first studied in un-treated animals. Afterwards, females and castrates were treated with a combination of testosterone-propionate (1 mg/kg) and 17P-oestradiolbenzoate(0.02 mg/kg) once every 3 days, for a period of 4 weeks. In untreated animals, males showed a considerably lower plasma clearance than females or castrates. This was accompanied by lower partial clearances for the production of two hydroxylated sulphadimidine metabolites. After hormonal treatment of females and castrates, sulphadimidine plasma clearance was significantly reduced, to values corresponding with those observed in control males. Furthermore, hydroxylation was significantly inhibited after treatment. The results indicate that sulphadimidine hydroxylation in the goat is performed by enzymes of the cytochrome P450 complex which are strongly influenced by gonadal hormones. Androgens seem to play a central role in this respect.     

Elimination of sulfamethazine residues from swine.

Tissue concentrations of sulfamethazine in swine fed the drug at the rate of 500 g/ton of ration (550 g/1,000 kg) for a 30-day period depleted to 0.1 ppm or less within 4 to 10 days after withdrawal of medicated feed. Depletion from the tissues and plasma of treated pigs showed a linear relationship with time when the concentrations were plotted on a semilogarithmic graph. Six untreated pigs that were placed on bedding in pens formerly occupied by the treated group developed tissue residues at or above 0.1 ppm sulfamethazine; the mean plasma concentration of sulfamethazine reached 2.8 ppm by day 15.     

The levels of zearalenone and its metabolites in plasma,urine and faeces of horses fed with naturally,Fusarium toxin–contaminated oats

Concentration profile of zearalenone (ZON) and its metabolites in plasma, urine and faeces samples of horses fed with Fusarium toxin–contaminated oats is described. In plasma, β‐zearalenol (β‐ZOL) was detected at high levels on day 10 of the study (3.21–6.24 μg/l). β‐Zearalenol and α‐zearalenol were the major metabolites in urine. Zearalenone, α‐ZOL and β‐ZOL were predominantly found in faeces. Zearalanone could also be detected in urine (1.34–5.79 μg/l) and faeces (1 μg/kg). The degree of glucuronidation was established in all sample types, approximately 100% in urine and plasma. Low per cent of glucuronidation (4–15%) was found in faeces samples. The results indicate the main conversion of ZON into β‐ZOL in horse. This finding could explain why horse is not susceptible to ZON in comparison with swine which produce α‐ZOL as a predominant metabolite.     

The effect of sex on antipyrine metabolism in cattle at different ages

The aim of this study was to determine the effect of sex on the metabolism of antipyrine by measuring the antipyrine plasma clearance as well as excretion of three major metabolites in urine in cattle of different ages. The experiment was carried out on 10 female and 10 male cattle of Black and White breed. The antipyrine test was carried out at 1, 2, 4, 6, 8, 12 and 18 months of age for each animal (single dose of 10 mg/kg antipyrine were given intravenously). The concentrations of antipyrine, 4-hydroxyantipyrine (4-OHA), 3-hydroxymethylantipyrine (HMA) and norantipyrine (NORA) were measured in plasma and urine by high performance liquid chromatography (HPLC). The apparent volume of distribution of antipyrine (aVd) decreased significantly between 1 and 18 months of age, but mean aVd values observed in males and females were not statistically different. The experimental period was characterised by a steady decrease (statistically significant) in antipyrine half-life (t1/2beta). These values did not differ significantly between males and females under 12 months. In 12 and 18 month-old animals the antipyrine half-life in the females was significantly shorter than in the males. The systemic clearance (Cls) of antipyrine increased significantly between 1 and 18 months of age. No significant differences were observed between systemic clearance of antipyrine in males and females under 12 months. In 12 and 18 month-old animals the Cls values were significantly higher in females than in males. Following intravenous administration, recovery of antipyrine and its three main metabolites increased significantly with age. These values did not differ significantly between males and females under 12 month of age. In 12 and 18 month-old females the excretion of 4-OHA and HMA in urine was significantly higher than in males at the same age. The excretion of NORA and unchanged antipyrine in males and females did not differ significantly. The partial clearances of antipyrine metabolites (Cl(m)) increased significantly between 1 and 18 months of age. No significant differences were observed between Cl(m) values in males and females under 12 months of age. In 12 and 18 month-old females the partial clearances of 4-OHA and HMA were significantly higher than in males. The clearance of NORA was significantly higher in 18 month-old females than in males. In conclusion, we report a sex-linked difference in plasma antipyrine clearance and urinary excretion of the main metabolites of antipyrine in cattle over 12 months of age, the females being the more active metabolizers.     

Effects of increasing lysine on carcass composition and cutting yields of immunologically castrated male pigs

The objective of this experiment was to determine if increasing lysine in the diets of immunologically castrated (IC) male pigs would increase percentage fat free lean and carcass cutting yields when compared with physical castrates. The anti-gonadotropin-releasing factor (GnRF) immunological product (Improvest, Pfizer Animal Health) is used worldwide to immunologically castrate entire male pigs to control boar taint and take advantage of the inherent ability of the entire male to deposit more muscle, less fat, and grow more efficiently than physically castrated males. The immunization process essentially allows the pig to grow as an entire male pig for most of its life and then removes any boar odor (boar taint) before slaughter. Reported lean meat advantages may also provide economic benefits to the domestic meat industry. Approximately 1,200 male pigs [physical castrates, IC males, and entire males] were each assigned to 1 of 4 diet programs which differed in lysine content. In each case, lysine was fed in a conventional step-down program that culminated with the following concentrations in the late finishing diet: physical castrates fed low lysine (0.7%), IC fed low lysine (0.7%), IC fed low/medium lysine (0.8%), IC fed medium/high lysine (0.9%), IC fed high lysine (1.0%), and entire males fed high lysine (1.0%). At 25 wk of age (5 wk post-second injection), pigs were individually weighed and the 2 pigs (n=96) in each pen closest to the median pig BW were selected and slaughtered. The right side of each carcass was dissected into soft tissue, skin, and bone. Proximate composition was determined on the soft tissue to determine percentage fat-free lean. The left side of each carcass was weighed and initially fabricated into ham, loin, belly, and whole shoulder. Each primal piece was weighed again and further fabricated into respective subprimal cuts. Immunological castration did not change (P>0.05) shear force values or ultimate pH when compared with either physical castrates or entire males. Marbling appeared to decrease as dietary lysine was increased among IC males. As expected, IC males had a greater (P<0.05) percentage fat-free lean than physical castrates but less (P<0.05) than entire males. Immunologically castrated males fed diets with medium/high and high lysine had greater (P<0.05) lean cutting yields and carcass cutting yields than physical castrates. Lean cutting yield and carcass cutting yields appeared to increase as dietary lysine was increased among IC males. Overall, immunological castration improved carcass cutability, increased percentage fat free lean, and had no effect on pork quality when compared with physical castrates.     

Utilisation d'acétate de mégestrol lors d'arrosage urinaire chez le chat mâle castré

The use of megestrol acetate to stop urine spraying in castrated male cats Four castrated male cats were treated with megestrol acetate because they were showing signs of urine spraying. The dosage used was 5 mg a day for seven days followed by 5 mg every three days for 21 days. The treatment did not exceed one month.     

Pharmacokinetics, metabolism, and renal clearance of sulfadiazine, sulfamerazine, and sulfamethazine and of their N4-acetyl and hydroxy metabolites in calves and cows

The effect of molecular structure on the drug disposition and protein binding in plasma and milk, the urinary recovery, and the renal clearance of sulfadiazine, sulfamerazine, and sulfamethazine and of their N4-acetyl and hydroxy derivatives were studied in calves and cows. Sulfadiazine was highly acetylated and was slightly hydroxylated. Sulfamerazine and sulfamethazine were hydroxylated predominantly at the methyl group of the pyrimidine side chain; hydroxylation of the pyrimidine ring itself was more extensive for sulfamethazine than for sulfamerazine. At dosages between 100 and 200 mg/kg of body weight, sulfamethazine had a capacity-limited elimination pattern, which was not observed for sulfadiazine or sulfamerazine. The concentrations of the parent sulfonamide and its metabolites in plasma and milk were parallel, the latter being lower. Metabolite concentrations in milk were at least 8 times lower than those of the parent drug. Metabolism speeds drug elimination, producing compounds with renal clearance values higher than those of the parent drug. The effect on the metabolism and renal clearance of methyl substitution in the pyrimidine side chain is discussed.     

Effect of sex on lipogenic activity in swine adipose tissue

Adipose tissue was obtained from male, female and male pigs castrated either at birth, 2 or 4 mo of age. Pigs were biopsied at 11 and 20 wk of age to obtain adipose tissue samples. Lipogenic capacity was assessed by measurement of in vitro glucose incorporation into lipids of adipose tissue slices. At 20 wk of age, males were less fat than females or males castrated either at birth or 20 mo of age. Adipocyte volume at 20 wk of age was smaller in males, females and recently castrated males (4 mo) than males castrated at birth or 2 mo of age. Lipogenic rate at 20 wk of age was lower in males than in castrated pigs; females had intermediate lipogenic rates. The results provide a partial metabolic explanation for the difference in subcutaneous fat deposition in the sexually diverse groups. There was no effect of estradiol-17 beta or testosterone in vitro on adipose tissue lipogenesis, suggesting that sex hormone effects in vivo may not be involved in short-term regulation of lipogenesis.     

Delayed physeal closure associated with castration in cats

Radiographs of 152 cats under four years of age were examined for evidence of physeal closure. Radiographic closure was compared between entire male, castrated male, and female (neutered and entire] cats. Physeal closure in castrated males was delayed when compared to that of entire males.     

An apparatus for quantitative collection of urine from male cattle, sheep, and swine

An apparatus for quantitative collection of urine from male cattle, sheep, and swine was designed. The apparatus was constructed of elastic, waterproof cloth, fabric fastener, and a waterproof bag. The apparatus was lightweight, easily installed on the animal, resulted in no apparent discomfort to the animal, and could be used for extended collection periods.     

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.     

Distal renal tubular acidosis in a cat with pyelonephritis

A four-year-old castrated male domestic shorthair cat with recent onset of lethargy and depression was found to have hypokalaemia, low plasma bicarbonate concentration and a urine pH of 7. Subsequent findings of hyperchloraemic metabolic acidosis with failure to produce acid urine led to a diagnosis of distal renal tubular acidosis. Pyelonephritis associated with Escherichia coli infection of the urinary tract was also diagnosed. The urinary tract infection was eliminated by antibiotic treatment. For two years subsequently, the clinical effects of distal renal tubular acidosis have been controlled by oral administration of potassium bicarbonate, although some biochemical abnormalities have persisted.     

Energy and protein requirements of weaned male and female Saanen goats

The objective of this research was to estimate the energy and protein requirements for maintenance and growth in male (castrated and intact) and female Saanen goat kids between 15 and 30 kg BW. To determine the net energy requirements for maintenance (NE_m) and the net protein requirements for maintenance (NP_m), 75 goats (25 castrated and 26 intact males and 24 females) were used. Twenty‐one goats (seven castrated and eight intact males and six females) were randomly assigned for slaughter to estimate the initial empty body composition. The 54 remaining animals (18 castrated and 18 intact males and 18 females) were randomly assigned in a split‐plot design using a 3 × 3 factorial arrangement with three sexes and three levels of intake (ad libitum and restricted feed to 75% or 50% of the ad libitum intake). Within each sex, six blocks (three goats per block) were formed and one goat was randomly assigned to each level of intake. The 75% and the 50% of ad libitum rationing were determined daily, based on the DMI of the animal fed ad libitum on the previous day. All animals within block were slaughtered when the animal fed ad libitum reached 30 kg BW. The net energy requirements for gain (NE_g) and the net protein requirements for gain (NP_g) were obtained using 58 animals (20 castrated and 20 intact males and 18 females). The animals were fed ad libitum and slaughtered at targeted BW (15, 23 or 30 kg). Sex did not affect NE_g and NP_m (277.8 kJ/kg^0.75 BW day and 2.98 g CP/kg^0.75 BW day respectively), as well as NP_g (180.9 ± 6.48 g/kg EBW gain) in Saanen goat kids. However, castrated males and females had similar NE_g (varied from 12.6 ± 0.424 to 17.9 ± 1.38 MJ/kg EBW gain), greater than intact males (varied from 9.74 ± 0.420 to 10.7 ± 0.984 MJ/kg EBW gain), as the BW increased from 15 to 30 kg.