ABSTRACT The objective of this study was to explore the impact of thermal stress on hormonal level and antioxidant activity in goats during various phases of the estrous cycle in the Egyptian summer. Forty cycling does were allocated to two groups (20 animals each) divided by season (mild/hot). Daily meteorological, rectal temperature, and respiratory rate data were recorded in the two seasons. The estrous cycle of the goats was synchronized by two intramuscular injections of 5 mg of prostaglandin F2α (PGF2α) at 11-day intervals. Blood samples were collected every two days and the levels of total antioxidant, malondialdehyde, and β-carotene were estimated. Total protein, albumin, cholesterol, triglycerides, progesterone, and thyroxine (T4) hormones were additionally measured in the serum of the collected samples. Under hot circumstances, both rectal temperature and respiratory rate increased considerably, with significant variation during the different stages of the estrous cycle. On the other hand, serum level of total protein, albumin, cholesterol, and triglycerides reduced significantly in animals in the hot environment, particularly during the luteal period of the estrous cycle (IV). During the Egyptian hot summer, the serum level of progesterone and T4 hormones declined in phases II and IV of the estrous cycle for progesterone and T4, respectively. Moreover, the serum content of all oxidative stress markers tested (total antioxidant, β-carotene, and malondialdehyde) decreased considerably, especially in estrous cycle phase II in the hot environment. The Egyptian environmental conditions have detrimental effects on some antioxidant agents and some biochemical parameters throughout the estrous cycle of goats.

ABSTRACT The objective of the present study was to assess the effect of dietary supplementation of Omega-3 plus on some the physiological and biochemical traits in growing Baladi goats under hot summer conditions. Thirty-four growing male goats (4-5 months old) were randomly divided into two equal groups. Animals in group 1 were fed a concentrate feed mixture (CFM), which was the control group. Goats in group 2 (the experimental group) were offered Omega-3 plus (1,000 mg/animal day-1) (30% fish oil, containing 18% eicosapentaenoic acid and 12% docosahexaenoic acid + 100 mg wheat germ oil (0.22% tocopherols)) daily in addition to the basal diet for four months (the experimental period) during the hot summer season. Body weight (BW) changes of both groups were recorded monthly during the experiment. Blood samples were collected monthly, and total protein, immunoglobulin G (IgG), total cholesterol, triglycerides, liver enzymes (AST and ALT), blood urea nitrogen, serum creatinine, and thyroid hormones (T3 and T4) were estimated. A significant increase in the live BW of growing goats was recorded as a result of dietary supplementation of Omega-3 plus. Total protein, IgG, and T3 levels were higher than those obtained with control. In contrast, total cholesterol, triglycerides, urea, ALT, and AST levels were significantly reduced. The serum concentration of creatinine and T4 levels was indistinguishable from those of control. Addition of Omega-3 plus as a dietary supplement to growing goats under hot summer conditions increases their daily weight gain and improves their general physiological and biochemical status by decreasing total cholesterol, triglycerides, urea, ALT, and AST. It is thus suggested that Omega-3 plus should be used as a supplement in the growth period of goats.