Efficiency of the experimental diet enriched with palmyrah ( Borassus flabellifer L.) fruit pulp on growth, pigmentation, immune challenge, and breeding performance in the guppy ( Poecilia reticulata) )

Many ornamental fish feeds currently use expensive and unsustainable synthetic color enhancers. However, potential untapped natural sources are available. Therefore, the study investigated the effect of palmyrah-enriched fruit pulp (PFP) on the growth, pigmentation, breeding performance, and immune challenge of guppies. Three-week-old male fries (450) (body weight of 122 +/- 1 mg) were randomly distributed with 30 fish/tank (five treatments with three replications) for 72 days. They were fed diets labelled PG-0 (Control), PG-1, PG-2.5, and PG-5, contained PFP at 0, 1, 2.5, and 5 %, respectively. The fish were hand-fed ad libitum to visual satiation thrice daily for the first month and twice thereafter. The PEP-included diet-fed fish showed higher growth performance (P<0.05) than the control. Regression analysis showed a consistent increase in the weight (R-2>0.98). The fish's carotenoid content (TCC) increased as the inclusion level of PFP was increased. However, there was no significant difference in the TCC in the fish between the PG-5 diet and the commercial group (Com). Adding 1 % of PFP to the fish diet increased the TCC in the tail to 6.83 +/- 0.08 <mu>g/g. Nevertheless, including the PFP above 1 % did not yield additional enhancement in tail TCC. This result is comparable with the MATLAB analysis of the digital photographs. Mortality of P. reticulata increased (P<0.05) after a 20-day exposure to Pseudomonas aeruginosa, while 50 % mortality decreased (P<0.05) with an increase in PFP inclusion. Meanwhile, PG-5-fed fish and com-feed-fed fish showed higher specific growth rates. Breeding performance showed no significant difference (P<0.05) in the mean fry production. Around 87 % of fish fry survived when fed with 5 % PFP compared to other diets. This study confirmed that all PFP-enriched diets improved the growth and immune response of guppies. Diet PG-1 notably enhanced the colouration, highlighting PFP's potential as a natural carotenoid source and sustainable alternative to synthetic pigmentation sources.