Improved sperm DNA integrity and altered fat metabolism and intestinal morphology in Nile tilapia (Oreochromis niloticus) males fed rations with purified nucleotide

Abstract

In this study, we assessed the health, growth, sperm characteristics, and intestinal, liver, and testicular morphology of Nile tilapia (Oreochromis niloticus) males fed rations containing purified nucleotides (NT). A total of 420 females (286 ± 7.15 g) and 140 males (536 ± 13.4 g) were used. Fish were fed on extruded ration (280 g digestible protein kg−1; 11.72 M joule (MJ) of digestible energy kg−1) containing 0.0, 2.5, 5.0, 7.5, and 10.0 g NT kg−1 for 150 days. After mating in hapas, sperm, blood, and tissue samples were collected for spermatic, hematological, biochemical, morphological, and centesimal composition analyses. Males fed on rations containing NT released sperm with a higher (p < 0.05) amount of spermatozoa with undamaged nuclear chromatin and a higher gonadosomatic index (p < 0.05). Growth was not affected (p > 0.05); however, males fed with 7.5 g NT kg−1 presented the smallest (p < 0.05) hepatosomatic index, whereas those fed with any of nucleotide levels had a reduced (p < 0.05) viscerosomatic index. Males fed NT had reduced (p < 0.05) hepatic fat content, and those fed 2.5 and 5.0 g NT kg−1 presented with the lowest (p < 0.05) liver fat content. Visceral fat content was not affected by the ration (p < 0.06). The biochemical composition of the muscle and testis was not affected (p > 0.05) by the ration. Plasma triglyceride levels were reduced (p < 0.05) in males fed the NT diet. Males fed 10 g NT kg−1 had the highest (p < 0.05) plasma high-density lipoprotein (HDL) levels, while those fed 5.0 g NT kg−1 presented the highest (p < 0.05) plasma glucose levels. Hematological parameters were not affected (p > 0.05) by the ration. Males fed 5.0 g NT kg−1 presented the highest (p < 0.05) intestinal viscosity, whereas those fed 2.5 and 5.0 g NT kg−1 had the highest (p < 0.05) enterocytes. The other morphological and morphometric parameters of the intestine, liver, and testis were not affected (p < 0.05) by the ration. The feeding of Nile tilapia breeders with rations of at least 2.5 g NT kg−1 boosted reproductive parameters and provided positive regulation of fish metabolism, resulting in better gonadal and spermatic status as well as a better hepatic and intestinal conditions.