Serum luteinising hormone, testosterone and total cholesterol levels, libido and testicular histomorphology of male West African Dwarf goats orally or subcutaneously treated with monosodium l-glutamate

This study investigated the effects of administration of monosodium l-glutamate (MSG) on serum luteinising hormone, testosterone and cholesterol levels, libido and testicular histomorphology of male West African Dwarf (WAD) goats. Thirty-two WAD goats (28 males and four females) were used for the study. The 28 males were randomly assigned to seven groups (A, BO, BS, CO, CS, DO and DS) of four goats each. Goats in groups BO, CO, and DO were given MSG orally at doses of 0.25, 0.50 and 1 g/kg body weight respectively for 28 days, while groups BS, CS and DS goats were given MSG subcutaneously at doses of 0.25, 0.50 and 1 g/kg body weight, respectively, for 28 days. Group A goats served as untreated control. The four female goats did not receive MSG, but were used to assess the levels of expression of libido by all the males. Serum luteinising hormone and testosterone were assayed prior to MSG administration (Day 0) and on Days 2, 14 and 28 of MSG administration, while serum cholesterol was assayed on Days 0, 14 and 28 of MSG administration. Libido scores and testicular histomorphology were evaluated on Days 26 and 28 of MSG administration, respectively. Results showed that on Days 14 and 28 of MSG administration the mean serum luteinising hormone, testosterone and cholesterol levels of the treated groups were significantly (P < 0.05) lower than those of the control group. The mean libido scores of all the treated groups were significantly (P < 0.05) lower than that of the control. Sections of the testes of the male WAD goats that received varying doses of MSG orally or subcutaneously showed no obvious lesions; the seminiferous tubules and interstices were normal and comparable to those of the untreated control. It was concluded that MSG administration for up to 14 and 28 days led to a significant lowering of serum luteinising hormone, testosterone and cholesterol, as well as libido scores.