Effects of Diet and Social Housing on Reproductive Success in Adult Zebrafish, Danio rerio

Abstract

Zebrafish (Danio rerio) have proven their efficiency as an animal model for genetics and development, but their nutrition and housing requirements continue to elude researchers. Diet and housing density were predicted to affect weight change and reproductive success in 120 days postfertilization (dpf) zebrafish, and growth performance of their progeny. Fish were fed one of four diets, each utilizing a different primary protein source (fish meal [Zeigler™], algae, or insect), while being housed 3.3 or 6.6 fish/L for 3 weeks. Clutch size, viability, and larval development of their progeny were monitored out to 10 dpf. All diets were sent out for proximate nutrient analysis and fatty acid profiles to understand how diet compositions affect reproduction. We found that diet and housing proximity affected adult fish weight and larvae growth; diets composed of higher levels of protein and polyunsaturated fatty acids (specifically arachidonic acid [AA] and eicosapentanoic acid) allowed fish to gain weight and produce healthy larvae. Fish housed at higher densities produced smaller embryos, but larger larvae than those housed at lower densities. These findings imply that significant effects of a modified stimulus are exhibited after relatively short periods.

Keywords: algae; fishmeal; insect; nutrition; social housing.

FIG. 1.

F1 weight change between breeding events for each feeding and housing treatment. Each colored line (dotted or solid) represents one tank (LGH: 6 fish each; DGH: 12 fish each) from each treatment. Horizontal solid orange lines indicate the initial average weight of fish per tank. Vertical solid black lines indicate growth intervals (d129: start of foreign diet treatments; d136–137: second breeding event, end of week 2; d138–143: end of week 3; d150–151: third breeding event, end of week 4). Arrowheads indicate final weight (averaged from each tank). Asterisks indicate statistical significance. (a–c) LGH fish fed Zeigler, algae, and insect, respectively. Dotted black line indicates the average weight change of fish per tank. (d–f) DGH fish fed Zeigler, algae, and insect, respectively. Solid black line indicates the average weight of fish per tank. DGH, densely group-housed; LGH, lightly group-housed. Color images available online at www.liebertpub.com/zeb

FIG. 2.

Main effects of diet treatments (blue: Zeigler; green: algae; tan: insect) and housing treatments (LGH; DGH) on F2 embryo size. Brackets signify significance after paired two-tailed t-tests. (a) Yolk sac diameter at 1 dpf; n = 100 ± 10 for each data set. (b) Chorion diameter at 1 dpf; n = 100 ± 10 for each data set. dpf, days postfertilization. Color images available online at www.liebertpub.com/zeb

FIG. 3.

Main effects of diet treatments (blue: Zeigler; green: algae; tan: insect) and housing treatments (LGH; DGH) on F2 larvae size. Brackets signify significance after paired two-tailed t-tests. (a) Total length of larvae at 5 dpf; n = 50 ± 10 for each data set. (b) Total length of larvae at 10 dpf; n = 50 ± 10 for each data set. Color images available online at www.liebertpub.com/zeb