The influence of coconut oil on the growth, immune, and antioxidative responses and the intestinal digestive enzymes and histomorphometry features of Nile tilapia (Oreochromis niloticus).

The trials of finding non-conventional and alternative aquafeed ingredients are increasing. In this sense, this study evaluated the influence of coconut oil on the growth, feed utilization, immune, and antioxidative responses of Nile tilapia. Five test diets were formulated by mixing coconut oil with the other ingredients at 0, 1, 2, 3, and 4% of the total ration and presented for tilapia for 60 successive days. The final weight, SGR, weight gain (WG), and feed intake were superior in fish delivered 2% of coconut oil (P < 0.05). Concurrently, fish that received 2% coconut oil had lower FCR and higher PER than fish of the control and 4% groups (P < 0.05). Higher lipase activity was observed in fish of 2% and 3% levels than the remaining groups (P < 0.05). Besides, the amylase and protease activities of fish in 1%, 2%, and 3% groups were higher than the 0% level (P < 0.05). The total blood cholesterol, RBCs, and PCV showed higher values in Nile tilapia fed 2% and 3% coconut oil (P < 0.05). The lysozyme and phagocytic activities were higher in fish fed 2% and 3% levels than the control (P < 0.05), while the phagocytic index in 2% and 3% levels was higher than 0% and 4% levels. Furthermore, SOD and CAT were higher in fish fed 1%, 2%, and 3% than fish fed 0% and 4% levels while GSH was higher in fish of 1%, 2%, and 3% than fish fed 0% level (P < 0.05). However, the MDA level was markedly lower in fish fed 25, 3%, and 4% coconut oil than the 0% level (P < 0.05). The intestine's histological structure in all groups appeared normal, forming of intestinal villi projecting from the intestinal wall. Also, the structure of the hepatopancreas had a normal architecture in all groups. To sum up, the inclusion of coconut oil at 2 to 3% is recommended as a replacer for fish oil in Nile tilapia diets.

Effect of dietary supplementation with apple cider vinegar and propionic acid on hemolymph chemistry, intestinal microbiota and histological structure of hepatopancreas in white shrimp, Litopenaeus vannamei.

This experiment was conducted to evaluate the effects of dietary supplementation of Apple cider vinegar (ACV) and propionic acid (PA) on biochemical parameters of hemolymph, intestinal microbiota and histology of hepatopancreas in white shrimp (Litopenaeus vannamei). Five experimental diets were evaluated in this study including diets supplemented with 1.0, 2.0 and 4.0% of ACV, 0.5% propionic acid, and a control diet with no supplements. Shrimps (initial weight of 10.2 ±â€¯0.04 g) in triplicate groups with the density of 25 shrimps per tank were fed the diets for 60 days. At the end of the feeding trial, shrimps fed with ACV and PA supplemented diets had significantly higher total protein level than those fed the control diet (P < 0.05). The number of Vibrio spp., R-cells (lipid storage cells) of hepatopancreas and cholesterol level in shrimps fed the diets containing ACV and PA were lower compared to the control group (P < 0.05). However, there was no remarkable variations in glucose concentration, B-cell number and tubule diameter among the experimental diets (P > 0.05). In addition, shrimps fed the ACV diets had significantly lower total heterotrophic marine bacteria compared to the control or PA groups, and the lowest bacterial number was observed in shrimp fed 4% ACV supplemented diet (P < 0.05). Supplementation of 2 and 4% ACV as well as 0.5% PA in the diet led to a significantly higher calcium concentration than the control treatment (P < 0.05). The lowest triglyceride concentration was observed in the shrimps fed diets containing 2.0 and 4.0% ACV, which resulted in 15 and 20% reduction, respectively (P < 0.05). Overall, the findings indicates that ACV and PA possess antimicrobial activity and demonstrate beneficial effects on health status, so they can be potentially used as feed additive in the feeding of L. vannamei.