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A 30‐day research was carried out to examine the impacts of dietary taurine (Tau) on ovaries maturation and physiological responses of Penaeus vannamei female brooders (29.4 ± 0.2 g). A basal diet (497 g kg−1 protein and 140 g kg−1 lipid) was administered with graded levels of Tau ranging from 0 (control) to 2, 4, 6, 8, and 10 g kg−1. A total of 180 shrimp brooders were stocked into 18 250 L black circular polyethylene tanks. Female (n = 5) and male (n = 5) shrimps were stocked in each tank and supplied with seawater (35.2 ± 3.1 g L−1 salinity, 28.9 ± 1.4°C) and the experimental feeds were offered to shrimp twice a day at 5% of their biomass. Supplementing diet with 4–8 g Tau kg−1 reduced latency period after eye stalk ablation to spawning (5–6 days) that was associated with higher hepatopancreatic and gonadosomatic (except for 8 g Tau kg−1 diet) indices (p < 0.05). With 10 g Tau kg−1 diet hepatopancreas glutathione peroxidase activity and total antioxidant capacity increased and catalase activity increased by 6 g Tau kg−1 diet. Supplementing diet with Tau‐enhanced bile‐salt dependent lipase activity in the gut. Docosahexaenoic acid and Tau levels were elevated in the ovaries with the increment of dietary Tau level (p < 0.05). Plasma total protein, calcium, cholesterol, and high‐density lipoprotein increased with inclusion of 6–10 g Tau kg−1 diet. The transcription levels of vitellogenin, insulin-like growth factor II, superoxide dismutase, prophenoloxidase, and lysozyme genes transcription levels were upregulated in the hepatopancreas of shrimp brooders fed 6–10 g Tau kg−1 diet (p < 0.05). It seems that Tau at 4–8 g kg−1 diet by modulating lipid metabolism, antioxidant capacity, and immunocompetence can improve maturation and health status of P. vannamei brooders. [ABSTRACT FROM AUTHOR]

Lecithotrophic larvae utilize extensive yolk reserves for early development. In this study, the effect of egg docosahexaenoic acid (DHA):eicosapentaenoic acid (EPA) ratios (i.e., 5.92, 10.08, 11.66, and 14.53) on the emerging larvae foregut development of rainbow trout was examined. Larvae samples were taken from day 22 to 36 post-fertilization. Thin whole body longitudinal sections were prepared and stained by Hematoxylin and Eosin and Alcian blue procedure. The sections were examined regarding epithelial layer thickness, intestinal fold height and mucosal layer thickness along with number of enterocytes and goblet cells. Results indicated that maximum thickness of the epithelium was observed on day 36 post fertilization in larvae hatched from eggs with DHA:EPA ratios of 14.53 and 10.08. The highest and lowest intestinal folds height were also observed in larvae hatched from eggs with DHA:EPA ratios of 10.08 and 14.53, respectively. The mucosal-submucosa layer thickness was the highest in larvae hatched from eggs with DHA:EPA ratio of 10.08. Enterocyte's count was the highest in larvae obtained from eggs with DHA:EPA ratio of 10.08 on day 36 post-fertilization. The highest and lowest number of goblet cells were enumerated in larvae obtained from eggs with DHA:EPA ratios of 5.53 and 14.53, respectively. In conclusion, our results revealed that feeding rainbow trout broodstock with diet contained highly unsaturated fatty acids (HUFA):polyunsaturated fatty acids (PUFA) ratio of 0.28 could result in the egg with DHA:EPA ratio of 10.08 which in turn yielded larvae with better foregut development parameters compared to those larvae emerged from the eggs with increased DHA: EPA ratio. [ABSTRACT FROM AUTHOR]

A 90‐day feeding trial was carried out to examine the influence of fish oil (FO) substitution with blends of vegetable oils (VOs) on reproductive efficiency of female brooders and fluctuation in fatty acid (FA) profile of embryos in Oncorhynchus mykiss. A basal diet was formulated in which 20% (80FO/20VO), 50% (50FO/50VO), 75% (25FO/75VO) and 100% (100VO) of FO were replaced by mixture of VO. Reproductive performance of brooders was not affected by drastic alternations in FA profile of diets. The level of saturated and monounsaturated FAs (MUFAs) significantly increased, whereas the levels of long‐chain polyunsaturated FAs (LC‐PUFAs), mainly docosahexaenoic acid, profoundly decreased during embryogenesis. The concentrations of MUFA and n−6 PUFA increased in the eggs with increasing the incorporation of VO mixture in diets; however, the concentration of LC‐PUFA and n−3/n−6 PUFA ratio decreased. Haematological parameters and humoral immune responses including total immunoglobulin content, lysozyme and alternative complement pathway activities in brooders fed with the experimental diets did not statically different. In summary, incorporating mixture of various VO sources especially linseed and sunflower oils as good sources of α‐linolenic and linoleic acids, respectively, along with low levels of residual fat from fish meal in diet suggested a good strategy for providing the appropriate essential FA requirements of O. mykiss brooders for their successful reproduction. [ABSTRACT FROM AUTHOR]