Enhancing reproductive capacity in hybrid Red Tilapia (Oreochromis niloticus ×‎ O. mossambicus) via dietary administration of date palm pollen (Phoenix dactylifera L.)‎

Abstract

Date palm pollen (DPP), a natural resource derived from male flowers of Phoenix dactylifera, is a rich source of nutrients with potential as a valuable dietary supplement. While DPP may offer various health benefits, including potential positive effects on reproductive performance in mammals, its impact on reproductive health in fish remains largely unexplored. This trial aimed to discover the consequences of dietary administration of DPP on blood biochemistry, reproductive hormone levels, digestive enzyme activities, gonadal histology, reproductive performance, and the expression of reproductive-related genes in Red Tilapia broodstock (Oreochromis niloticus ×‎ O. mossambicus). Red Tilapia broodstock (150 ± 5.77 g), with a female: male ratio of 3:1, were fed an isonitrogenous and isocaloric basal diet (DPP0) or diets supplemented with 10 g (DPP10), 20 g (DPP20), and 40 g (DPP40) of DPP per kilogram of diet for a period of two months. GC-MS analysis of DPP revealed the presence of several bioactive compounds, including butan-1-one, tetradecanoic acid, cholestan-3-one, octasiloxane, and heptasiloxane, which have been reported to exhibit promising antimicrobial, antioxidant, and immunomodulatory properties. The results demonstrated that fish fed diets supplemented with 20 g or 40 g of DPP exhibited significantly higher levels of total protein, albumin, and globulin compared to the control group (P < 0.01). All DPP-supplemented groups displayed a significant decrease in aspartate (AST), and alanine (ALT) aminotransferases, and alkaline phosphatase (ALP) levels compared to the control group (P < 0.01). The lowest values for these parameters were observed in the DPP40 group. Lipase activity was significantly improved by DPP dietary inclusion, while amylase activity remained unaffected (P > 0.05). Regarding reproductive hormones, testosterone levels in males were significantly increased only in the DPP40 group, while FSH, E2, progesterone, and LH were significantly elevated in all fish fed DPP in their diets (P < 0.001) related to DPP0 group. The GSI (%) and HIS (%), mean number of fry/fish, egg diameter (mm), and their weights were improved in all DPP fish groups compared to the DPP0 group. The mRNA expression levels of reproductive-related genes, including FSHR, CYP1A, ESR1, FOXL2A, and ESR2A were significantly upregulated in the gonads of fish fed DPP diets compared to the control group (P < 0.05). The gonadal histology demonstrated that DPP boosted gonad maturation histo-structure in both genders of Tilapia fish. This study demonstrates that dietary administration of DPP can significantly enhance reproductive performance in Red Tilapia by upregulating the expression of key reproductive genes and improving overall health status. These findings suggest that DPP has the potential to be a promising natural feed additive for sustainable aquaculture, particularly in enhancing the reproductive capacity of Red Tilapia broodstock.