Effects of vitamin E and astaxanthin supplementation on maturation of male white shrimp Penaeus vannamei

Abstract

This study was to determine effects of dietary vitamin E and astaxanthin on maturation of male white shrimp Penaeus vannamei. The experiment was conducted using 3x3 factorials involved completely randomized design. The Combinations of 3 levels of vitamin E (200, 400 and 600 ppm) and 3 levels of astaxanthin (100, 300 and 500 ppm) were prepared from the same basal diet. Five month-old P. vannamei males were selected from an intensive rearing pond. At the beginning, only shrimp with no appearance of spermatophores were used for the experiment. The feeding experiment was operated 40 days in 8 replications. The results showed no interactions between dietary vitamin E and astaxanthin on growth, survival, reproductive performances (spermatophore weight, amounts of sperm, percentage of live and abnormal sperm), and vitamin E and astaxanthin content in whole body. Both vitamin E and astaxanthin had no significant effect on growth. Astaxanthin had also no significant effect on survival rate of the shrimp. For vitamin E, shrimp fed diets supplemented with 600 ppm vitamin E had significantly higher survival rate than those fed 200 ppm (P<0.05). Effects on reproductive performances: significantly higher mean of spermatophore weight was observed in shrimp fed diets with vitamin E 400 ppm, compared to those fed diets with vitamin E 200 and 600 ppm (P<0.05), while astaxanthin at 500 ppm provided significantly higher spermatophore weight than those shrimp fed diet containing 300 ppm astaxanthin (P<0.05). For sperm counts, all levels of astaxanthin showed no significant effect on number of sperms per spermatophore but vitamin E at 400 ppm had significantly higher sperm number than those fed with vitamin E 200 and 600 ppm (P<0.05). Shrimp fed with vitamin E 400 and 600 ppm had significantly greater live sperms than those fed 200 ppm (P<0.05) while astaxanthin showed no effect on live sperms. Percentage of abnormal sperms investigated as percentage of abnormal body sperm indicated no significant effect of both vitamin E and astaxanthin, when evaluated in term of percentage of abnormal spike, vitamin E enriched diets did not show any significant difference but shrimp fed diets containing astaxanthin 300 and 500 ppm had significantly lower abnormal spike than those fed diet containing 100 ppm of astaxanthin (P<0.05). Vitamin E content in all tissues was no significant effect among levels of both vitamin E and astaxanthin. However, vitamin E content in hepatopancreas was higher than in muscle at the same level of both vitamin E and astaxanthin (P<0.05). For astaxanthin accumulation, both vitamin E and astaxanthin had no effect on astaxanthin accumulation in hepatopancreas (P<0.05). In muscle, vitamin E had no significant effect among levels on astaxanthin content, while shrimp fed with astaxanthin 500 ppm had significantly higher astaxanthin content than those fed 100 ppm. At the same level of astaxanthin, shrimp fed with astaxanthin 300 and 500 ppm had higher astaxanthin contentin hepatopancreas than in muscle, but shrimp fed with astaxanthin 100 ppm had no significant effect between muscle and hepatopancreas. The present study suggested that supplementation of vitamin E and/or astaxanthin in practical shrimp diets as appropriate amount can enhance reproductive performance in male white shrimp P. vannamei.