Nutritional programming improves dietary plant protein utilization in zebrafish Danio rerio

Abstract

Nutritional Programming (NP) has been shown to counteract the negative effects of dietary plant protein (PP) by introducing PP at an early age towards enhancement of PP utilization during later life stages. This study explored the effect of NP and its induction time on growth, expression of appetite-stimulating hormones, and any morphological changes in the gut possibly responsible for improved dietary PP utilization. At 3 days post-hatch (dph) zebrafish were distributed into 12 (3 L) tanks, 100 larvae per tank. This study included four groups: 1) The control (NP-FM) group received fishmeal (FM)-based diet from 13-36 dph and was challenged with PP-based diet during 36-66 dph; 2) The NP-PP group received NP with dietary PP in larval stage via live food enrichment during 3-13 dph followed by FM diet during 13-36 dph and PP diet during 36-66 dph; 3) The T-NP group received NP between 13-23 dph through PP diet followed by FM diet during 23-36 dph and PP diet during 36-66 dph; and 4) The PP group received PP diet from 13-66 dph. During the PP challenge the T-NP group achieved the highest weight gain compared to control and PP. Ghrelin expression in the brain was higher in T-NP compared to NP-FM and NP-PP, while in the gut it was reduced in both NP-PP and T-NP groups. Cholecystokinin expression showed an opposite trend to ghrelin. The brain neuropeptide Y expression was lower in NP-PP compared to PP but not different with NP-FM and T-NP groups. The highest villus length to width ratio in the middle intestine was found in T-NP compared to all other groups. The study suggests that NP induced during juvenile stages improves zebrafish growth and affects digestive hormone regulation and morphology of the intestinal lining-possible mechanisms behind the improved PP utilization in pre-adult zebrafish stages.

Possible Dietary Effects of Insect-Based Diets across Zebrafish (Danio rerio) Generations: A Multidisciplinary Study on the Larval Phase

“…Considering the orexigenic signals analyzed in the present study, all the groups fed BSF-based diets showed a significant ghrl , npy and cnr1 downregulation compared to F1Hi0. These results are in line with the biometric ones and with a previous study in which nutritionally programmed zebrafish were found to be in a satiated state compared to the control groups [ 80 ]. Conversely, the higher orexigenic signals gene expression found in all F0 zebrafish larvae fed on BSF-based diets was related to a compensatory mechanism that increased food intake with a consequent faster growth rate, possibly in relation to dietary deficiency of important nutrients, like DHA [ 8 , 30 ].…”

“…Nutritional programming may make it possible to obtain fish better adapted to use specific dietary ingredients, also by acting on the gastrointestinal tract which, in fish, is able to adapt to rapid shifts in environmental conditions, including diet [ 80 , 81 , 82 ]. In the present study, no specific inflammatory events and no differences in histopathological indexes were detected through the histological analyses on F1 zebrafish larvae intestine from any of the dietary treatments.…”

Nutritional Programming with Dietary Soybean Meal and Its Effect on Gut Microbiota in Zebrafish (Danio rerio)

“…6 NP with PP shows great promise to increase utilization of lower-quality PP sources. 1,5,[7][8][9] Studies have challenged rainbow trout (Oncorhynchus mykiss) with vegetable oil-based diets and reported that the fish later presented higher feed intake, growth, and feed utilization compared to nonprogrammed individuals. 1,10 Previous research has also provided insight that early NP of rainbow trout alevins might lead to similar alpha diversity measures of gut microbes between programmed versus nonprogrammed individuals.…”

Can intestinal absorption of dietary protein be improved through early exposure to plant-based diet?

“…In another study, NP with dietary carbohydrates from plant products initially improved growth performance in European sea bass (Dicentrarchus labrax) larvae; however, programming effects faded over time and no signifcant difference in growth was observed between programmed and nonprogrammed juveniles [31]. Interestingly, a similar study performed in our laboratory under the same conditions did find that NP improved growth performance of fish fed a SBM diet [32]. One possible explanation for the lack of programming influence in the present study could be species-specific differences.…”