Impacts of sex steroids and aromatase inhibitor on performances, carcass characteristics and gonadal histology of broiler chickens slaughtered at different ages.

This experiment was established to evaluate the influence of synthetic steroid hormone and aromatase inhibitor on performance, carcass characteristics, hormonal profile and gonadal structure of broiler chickens slaughtered at two different ages. A total of 360 Cobb Avian48 chicks were sexed and distributed randomly into three groups: Tam10 group; birds received Tamoxifen10mg (Tamfen 10 mg@ ) orally at a level of 10 mg/kg body weight daily from the 3rd till the 9th day of age; BOL group: birds injected intramuscularly with Boldenone undecylenate (BOLD-GAN@ 0.1 mg/kg) at the 5th and the 9th day of age; and Control group. BOL injection or Tam supplementation improved performance traits compared with the control group. Although Tam positive effect appeared early before the 5th week of age, the BOL effect was delayed to the 6th week. BOL injection improved carcass characteristics of both sexes at both 5 and 6 weeks slaughtering ages. Regardless of treatment effect, the mortality% was higher in the late weeks of age than in the early weeks. Moreover, BOL treatment increased comb% compared with control and Tam treatments. Generally, males had significantly higher testosterone levels and lower oestrogen levels than females. Males treated with Boldenone had the highest testosterone level, although testosterone levels did not differ considerably among females of the various groups. BOL treatment females had the lowest oestrogen level. Both Tam10 and Boldenone had adverse effects on testicular and ovarian histology, affecting the typical structures. Finally, we concluded that the anabolic effect of Tam10 may be achieved in griller broilers production without changing the sex hormones assay. Although Boldenone achieved an anabolic effect without changing blood sex hormone levels, this effect is induced early with females and delayed with males, which prolongs the marketing period. The goal is to shorten this period. Therefore, this material can only be used with the possibility of separating females from males to be used with females only.

Fundamental differences in patterns of retinal ageing between primates and mice.

Photoreceptors have high metabolic demands and age rapidly, undermining visual function. We base our understanding mainly on ageing mice where elevated inflammation, extracellular deposition, including that of amyloid beta, and rod and cone photoreceptor loss occur, but cones are not lost in ageing primate although their function declines, revealing that primate and mouse age differently. We examine ageing primate retinae and show elevated stress but low inflammation. However, aged primates have a >70% reduction in adenosine triphosphate (ATP) and a decrease in cytochrome c oxidase. There is a shift in cone mitochondrial positioning and glycolytic activity increases. Bruch's membrane thickens but unlike in mice, amyloid beta is absent. Hence, reduced ATP may explain cone functional decline in ageing but their retained presence offers the possibility of functional restoration if they can be fuelled appropriately to restore cellular function. This is important because as humans we largely depend on cone function to see and are rarely fully dark adapted. Presence of limited aged inflammation and amyloid beta deposition question some of the therapeutic approaches taken to resolve problems of retinal ageing in humans and the possible lack of success in clinical trials in macular degeneration that have targeted inflammatory agents.