androst-16-en-3-one and Body-Weight

The objective of this experiment was to compare the pork quality of entire male pigs and pigs immunized against GnRF (IC males) at both light (64.8kg) and heavy (106kg) liveweights and two feeding regimes (restricted at 2.5 times maintenance and ad libitum). There was no difference in objective measurements (P>0.05) or eating pork quality (P>0.1) between entire male and IC males. Fail rates were reduced by 9.1% and 12% for pork from IC males for quality grade (P=0.007) and re-purchase intention (P=0.001), respectively, compared to pork from entire males. Skatole (P=0.001) and androstenone (P<0.001) levels in belly fat were higher in entire male than IC male pigs. In addition, 37.5% of the light entire male pigs fed ad libitum showed skatole levels that exceeded the sensory threshold of 0.2μg/g. This work confirms that immunization against GnRF is effective in eliminating boar taint and reducing pork quality fail rates by approximately 10% compared to pork from entire males.

Topics: Abattoirs; Androstenes; Animal Feed; Animals; Body Weight; Diet; Gonadotropin-Releasing Hormone; Immunization; Male; Orchiectomy; Red Meat; Skatole; Swine

To investigate the extent to which the level of androstenone and skatole decreases with a decrease in live weight and/or age at slaughter of entire male pigs produced under organic standards, 1174 entire male pigs were raised in parallel in five organic herds, distributed across four batches in summer and winter. The median androstenone level was high for organic entire male pigs (1.9 µg/g), but varied greatly both within and between herds. Median skatole level was 0.05 µg/g, also with a wide range both within and between herds. Decreasing live weight over the range of 110 ± 15.6 kg s.d. was found to decrease androstenone as well as skatole concentration, however, with different patterns of association. Age did not have significant direct effect on either androstenone or skatole levels. Androstenone levels were higher during winter than summer (P<0.0001), but no difference in skatole was found between seasons. The study concludes that decreasing live weight at slaughter could be an applicable management tool to reduce risk of boar taint and the level of tainted carcasses for a future production of entire male pigs within the organic pig production system, although further studies are needed as great variation in boar taint was found also for low weight animals.

Topics: Age Factors; Androstenes; Animals; Body Weight; Male; Meat; Organic Agriculture; Seasons; Skatole; Sus scrofa; Swine

Societal pressure to ban surgical castration of male piglets is rising due to animal welfare concerns, thus other methods to prevent boar taint need to be explored. Genetic selection against boar taint appears to be a long-term sustainable alternative. However, as boar taint is linked to reproductive hormones, it is important to consider possible negative side effects such as delayed sexual maturity or changes in behaviour. We reported earlier that the melanocortin-4 receptor (MC4R) marker can be used to reduce boar taint levels in fat of boars. The objective of this study was to evaluate whether MC4R marker-assisted selection for lower boar taint prevalence affects plasma levels of boar taint compounds and testosterone; sexual maturity; behaviour; skin lesions; and lameness in boars and gilts. Using an intervention study with a 2×2 design, 264 boars and gilts differing on position 893 of the MC4R gene (AA v. GG) were compared. The MC4R polymorphism did not affect the plasma concentration of either androstenone or testosterone at different time points, whereas the concentration of skatole was significantly lower (P=0.003) and the concentration of indole tended to be lower (P=0.074) in GG compared with AA boars. A higher percentage of gilts of the GG genotype were in puberty at slaughter age compared with AA gilts (P<0.001). The age of the boars at sexual maturity (as indicated by the first positive preputial smear test) did not differ between AA and GG boars. In contrast, weight of GG boars at sexual maturity tended to be lower (P=0.065). During the period from 6 weeks of age to slaughter, boars and gilts of the GG genotype showed more playing behaviour (P=0.015) and less passive and feeding behaviour (P=0.003). They showed more skin lesions on their back and caudal area (P=0.022), and tended to show more skin lesions on their head and anterior area (P=0.093) compared with AA animals. In conclusion, the polymorphism in the MC4R gene can be used as a marker without negative effects on reproduction characteristics in boars and gilts. Genetic selection towards a lower prevalence of boar taint will lead to more active pigs with more skin lesions. Management strategies may therefore be necessary to reduce skin lesions in the selected animals.

Topics: Androstenes; Animal Welfare; Animals; Body Weight; Female; Genotype; Indoles; Male; Polymorphism, Genetic; Receptor, Melanocortin, Type 4; Reproduction; Sexual Maturation; Skatole; Swine; Testosterone

A study was conducted to elucidate the effects of social factors on the concentrations of boar taint substances, androstenone and skatole, in boars. The factors included dominance (social rank) and the effects of strongly tainted animals on other members of the group. Four successive replicates of 100 pigs (50 boars + 50 gilts) with an average live weight of 24 kg were randomly allocated to 10 pens of 10. Data for this study were collected during the period of 67 to 114 kg of live weight and included the repetitive recording of agonistic behavior during competitive feeding; blood sampling for determination of plasma androstenone, skatole and testosterone in boars; feces sampling for determination of skatole content; and collection of bulbourethral glands in boars, and uteri plus ovaries in gilts at slaughter, for the assessment of sexual maturity. Results show an influence of social rank on plasma concentrations of androstenone (P = .0001) and testosterone (P = .0001), the weight of the bulbourethral glands (P = .0001), and plasma skatole (P = .02). Pens were classified according to the pig with the highest concentration of androstenone in the pen into high, medium, and low maximum pens. In pens with high maximum concentrations of androstenone, the second-highest androstenone concentration (P = .0001), and the average concentration (P = .0003) in the pen were higher than those in pens with medium or low maximum concentrations of androstenone. Mean aggression level was also higher (P = .02), but pens with high maximum aggression level did not have higher mean androstenone concentration. Rank effect on androstenone was more important than aggression effect. Neither maximum androstenone concentration nor maximum aggression level in a pen was related to the pen mean stage of sexual maturity in either sex. No influences of rank, aggression, or aggression received were found on the feces skatole level, and no pheromonal communicative function was demonstrated for skatole. High androstenone concentrations did not have a suppressive effect on androstenone concentrations in other males of the group; on the contrary, the levels were increased. This may be due to a stimulating effect of androstenone and, possibly, mating activity. Consequently, in the production of boars for slaughter, strongly tainted animals should be avoided or removed and mating activity minimized. This could be facilitated by, for instance, slaughtering before sexual maturity or separate rearin

Topics: Abattoirs; Aggression; Androstenes; Animal Husbandry; Animals; Body Weight; Bulbourethral Glands; Feces; Feeding Behavior; Female; Male; Meat; Sexual Maturation; Skatole; Social Dominance; Swine; Testosterone; Uterus

The aim of the present experiment was to determine whether age, live weight, or a combination of both, was the most important factor influencing fat 5 alpha-androstenone levels in male pigs. Three groups of 50 boars each were fed either on a liberal plane of nutrition (CTRL group) or were restricted (SW and SA groups). Fat 5 alpha-androstenone was measured three times in each pig (on biopsies at two different times and at slaughter) at either the same live weight (SW) or at the same age (SA) as CTRL boars. In addition, the genital tract was dissected at slaughter. SW boars (aged 169 days) exhibited higher fat 5 alpha-androstenone levels than CTRL boars (aged 139 days) when the first biopsy was taken at 80 kg of live weight (1.2 vs 0.8 microgram/g; P less than 0.05). By the time of the second biopsy (100 kg of live weight) and at slaughter (125 kg) there was no significant difference between the SW and CTRL groups, although the SW were 43-55 days older than the CTRL. At all three measurement times, fat 5 alpha-androstenone was lower in SA than in CTRL boars which were 21-36 kg heavier (0.5 vs 0.8 micrograms/g at 139 days; 0.9 vs 1.3 micrograms/g at 160 days; 1.2 vs 2.0 micrograms/g at 185 days; P less than 0.001). Partial correlations between fat 5 alpha-androstenone and age were significant at the first biopsy, whereas partial correlations with live weight were significant at all three times of measurement. In SA boars weighing 90 kg there was a significant correlation between fat 5 alpha-androstenone and all the developmental traits of the genital tract. In SW and CTRL pigs weighing 125 kg, fat 5 alpha-androstenone was significantly correlated with accessory sex gland development but not with testis or epididymis weight. From the present data it is concluded that both age and live weight had a significant effect on fat 5 alpha-androstenone levels in young, light boars. In older, heavier boars, age had no effect per se but live weight still had a significant influence on 5 alpha-androstenone concentrations. In boars weighing 90 kg, fat 5 alpha-androstenone level depended on sexual maturity. When the animals were sexually mature at 125 kg of live weight, 5 alpha-androstenone level depended on the individual's potentiality for steroid production, which is probably under genetic control.

Topics: Adipose Tissue; Aging; Androstenes; Animal Nutritional Physiological Phenomena; Animals; Biopsy; Body Weight; Male; Swine

A simple, cheap and rapid method for the quantitative determination of the boar taint substance, 5 alpha-androst-16-en-3-one, in pig adipose tissue is described. After saponification of the fat the androstenone is extracted, derivatised with o-(pentafluorobenzyl)hydroxylamine hydrochloride in pyridine and analysed by fused-silica open-tubular capillary gas chromatography with electron-capture detection.

Topics: Adipose Tissue; Androstenes; Animals; Body Weight; Chromatography, Gas; Indicators and Reagents; Male; Orchiectomy; Swine

The effect of weight of fatty tissue on fat and plasma androstenone and on plasma testosterone relationships in the young boar was studied. For this purpose, hCG stimulation of steroid testicular production was performed in 12 boars and fat androstenone concentration subsequently measured. In addition plasma androstenone and testosterone were determined in 8 of them, previously cannulated. The results show that: 1) although plasma testosterone response to hCG stimulation was similar in all boars, fat and plasma androstenone responses were very variable between boars, 2) weight of fatty tissue appeared to have little influence, if any, on androstenone exchanges between plasma and fatty tissue and 3) plasma androstenone/testosterone ratio appeared to be less variable within boars than between boars. The data show that there is probably some between-boars-variability in the respective rates of elimination of testosterone and androstenone.

Topics: Adipose Tissue; Age Factors; Androstenes; Animals; Body Weight; Chorionic Gonadotropin; Male; Organ Size; Radioimmunoassay; Swine; Testosterone