Camel whey protein hydrolysate diet mitigates alkaline stress–induced biochemical disorders and restores the target of rapamycin, MAPK pathway, and autophagy-related gene expression in Nile tilapia.

Exposure to alkaline stress is common in aquatic practices. The present research investigated the detrimental impacts of rearing Nile tilapia under alkaline water stress by investigating the liver function indices and transcriptomic profile. A 30-day study was conducted on 160 fish (16.02 ± 0.14 g) split into four groups, each with four replicates. Group 1 (G1) and G2 were fed on a basal diet fortified with 0 and 75 g/kg diet camel whey protein hydrolysates (CWP) and reared in freshwater (carbonate alkalinity = 1.4 mmol/L, pH = 7.19). Moreover, G3 and G4 were fed on a basal diet enriched with 0 and 75 g/kg diet CWP and reared in alkaline water (carbonate alkalinity = 23.8 mmol/L; pH = 8.65). The outcomes revealed elevated lipid indices (triglycerides, cholesterol, low- and high-density lipoproteins) and liver enzymes (alanine and aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase) with lowered protein indices (total protein, albumin, and globulin) in alkaline-reared fish. Moreover, oxidative stress was initiated through lowered antioxidant enzymes (superoxide dismutase, catalase, and reduced glutathione) and higher malondialdehyde in the alkaline-exposed fish. Alkaline stress induced the activation of the mechanistic target of rapamycin and MAPK pathway (mitogen-activated protein kinase, c-Jun NH terminal kinase, and MAPK-1) with down-regulation of the autophagy-related genes (ATG-5, ATG-7, and ATG-13) and cathepsin B expression. Feeding on a CWP-supplemented diet resulted in significant modulation of the lipid profile, liver enzyme activity, and improvement in protein indices and antioxidant enzyme activity. Furthermore, modulation of the transcriptomic profile of the hepatic tissue of the alkaline-exposed fish was noticed due to feeding on a CWP-supplemented diet. Overall, CWP dietary addition at a level of 75 g/kg diet can alleviate the alkaline stress exposure in Nile tilapia. These outcomes could contribute to understanding the physiological circumstances of Nile tilapia when reared in alkaline water as well as provide a novel dietary additive for mitigating the bad consequences due to alkaline-stress exposure. [ABSTRACT FROM AUTHOR]