To establish an effective feeding regime for the aquaculture of genetically improved farmed Nile Tilapia Oreochromis niloticus (GIFT), this experiment investigated the effects of feeding frequency and daily ration on the growth of GIFT fry (initial weight, ca. 0.85 g). A factorial experiment design of two feeding frequencies (2 and 3 meals/d) and five feeding rates (2, 4, 6, 8, and 10% body weight per day [BW/d]) was carried out over 70 d with three replicates for each treatment. At the end of the experiment, fish from each treatment were sampled for the growth metrics of final body weight (Wt), weight gain rate (WGR), survival rate (SR), specific growth rate (SGR), and feed conversion ratio (FCR), as well as body composition and plasma metabolite measurements and histopathological analysis. The feeding frequency had a significant (P < 0.05) effect only on the Wt of fish. Feeding rates had highly significant effects on all the growth metrics (P < 0.01) except SR. The largest WGR and SGR were both observed in the fish receiving 6% BW/d at both feeding frequencies. The largest Wt was observed in the fish fed two meals daily at a 6% feeding rate. The relatively lower hepatosomatic index, liver contents, and body lipid also indicated better performance in fish that received 6% BW/d. In conclusion, these results suggest that a feeding rate of 6% BW/d and a feeding frequency of 2 meals/d is the most favorable protocol for the growth and physiological balance of GIFT during the fry phase.

Fatty liver disease is a growing problem in fish aquaculture and there is an urgent need to identify causes and possible remedies. In the present study, the effects of treating fatty liver disease in the Nile tilapia (Oreochromis niloticus Linnaeus, 1758) with an extract derived from a herb, Sedum sarmentosum Bunge (SSB), was investigated. We found that the SSB extract could restore the changes to feed coefficient, immune capacity, and pathological index caused by fatty liver disease, and also prevent apoptosis in hepatocytes. An RNA-seq analysis showed that treatment with SSB extract altered expression of genes in the lipid metabolic process, metabolic process, and oxidation-reduction process. Our results suggest that disorders of the PPAR and p53 signaling pathways may be involved in steatohepatitis development and in the therapeutic mechanism of the SSB extract treatment; these observations shed new light on possible treatment of steatohepatitis.

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As a reproductive regulating factor, vitamin E can promote gonad development by improving the levels of gonadal steroid hormones, and can also regulate reproduction by promoting the release of luteinizing hormone and follicle-stimulating hormone in the anterior pituitary (Zhou, 2005). Vitamin E can also protect sperm cells by preventing sperm oxidation which improve animal reproductive performance (Sheng et al., 2007). Li et al. (2018) found that adding 160 mg/kg of vitamin E to feed could significantly increase the gonadosomatic index (GSI) and the number of follicular cells in shrimp (Macrobrachiu nipponense). Vitamin E can also enhance the reproductive performance of animals by improving oviposition, hatching and the quality of germ cells. Studies have shown that adding proper amounts of vitamin E to feed could significantly

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