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Abstract Full Text

Effects of aestivation duration on testosterone, haemolymph biochemical parameters and reproductive tract dimensions and weight of giant African land snail (Archachatina marginata) during dry season.

Abstract

Aestivation is a process of metabolic inactivity under which energy reserve are manipulated for survival. Reproductive apparatus and haemolymph biochemical agents also undergo phase manipulation as the duration continues. To determine the physiological influence on key hormone of reproduction and reproductive apparatus, seventy five A. marginata snails were used for this study. The snails were divided into five treatments with fifteen replicate each. Treatment include: Zero (0) week, Three (3) weeks, Six (6) weeks, nine (9) weeks and six (6) weeks post-aestivation. Parameters measured were: Testosterone concentration, haemolymph biochemical parameters Total protein, albumin, globulin, Aspartate transaminase (AST) and Alanine transaminase (ALT), dimensions (length) and weight of the organs and tissues of the reproductive tracts (Ovo-testis, penis, vaginal, oviduct, little hermaphrodite duct, common hermaphrodite duct, vas deferens and albumen gland) gonado-somatic index and percentage mortality. Result showed that level of testosterone at three and six weeks of aestivation significantly reduced compared to the control. Also, at nine weeks of aestivation, the reduction was significantly greater than what was recorded at both three and six weeks of aestivation. But the testosterone levels were reversed at nine weeks post aestivation. Total protein and globulin were significantly influenced with both reaching a peak value at 9 weeks of aestivation while ALT, AST and albumin were not significantly affected. So also, of all the reproductive tract parts measured, organ weight, ovo-testis weight, penis weight and length were significantly influenced (P<0.001; P<0.001; P<0.05; P<0.001). Similarly, vaginal weight, oviduct weight, little hermaphrodite duct weight and length were also significantly affected together with vas deferens length and albumen gland length while aestivation duration had no significant influence on reproductive tract weight, ovo-testis length, vaginal length, oviduct length, little hermaphrodite duct length, vas deferens weight and albumen gland weight. Similarly, gonado-somatic index was also not significantly affected by aestivation duration. It was also obvious from this study that the highest mortality was recorded at 6 weeks of aestivation, followed by 9 weeks of aestivation while 3 weeks and 6 weeks post-aestivation had the least mortality with the control intact.