Influence of dietary fat level and increased adiposity on growth and fat deposition in rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract

Rainbow trout, Oncorhynchus mykiss (Walbaum), (initial weight µ 90 g) were fed diets differing in fat content (27.5% versus 12.6%) to examine the effects of dietary fat level on growth and fat deposition. During phase 1, which was run for 11 weeks, the fish were fed either a high-(27.5%) or low-fat (12.6%) diet. The fish were held at 14.5°C under a 24 h:0 h light:dark photoperiod and were fed for 4 h each day during this phase. Subsequently, in phase 2, both diets were presented simultaneously, and the influence of adiposity on growth and fat deposition was examined in a growth trial which lasted for 8 months. There were no significant differences in body weights at the end of phase 1 (360.7 Ϯ 7.7 g versus 348.2 Ϯ 18.7 g for the fish on the high-and low-fat diets, respectively), but body composition was influenced by the fat content of the diet. The trout fed the high-fat diet had higher viscerosomatic indices (VSI: 11.7 Ϯ 2.0% versus 9.1 Ϯ 0.7%) and higher visceral fat contents (per cent fat: 38.0 Ϯ 6.7% versus 23.3 Ϯ 3.7%) than trout fed the low-fat diet. The percentage fat contents of the carcass (per cent fat: 12.4 Ϯ 1.0% versus 9.3 Ϯ 0.7%) and whole body (per cent fat: 15.4 Ϯ 1.6% versus 10.5 Ϯ 0.7%) were higher amongst the trout fed the high-fat diet, and these fish had a higher energy gain than those fish fed the low-fat diet. Differences in adiposity between the trout fed the high-and low-fat diets did not result

Growth performance of juvenile pikeperch, Sander lucioperca (L.) fed graded levels of dietary lipids

“…The lipid content in feed is generally correlated with the increase of this nutrient in fish bodies (Shearer, 1994;Jobling et al, 1998;Koskela et al, 1998;Jobling, 2001;Sargent et al, 2002). In the present study the chemical composition of pikeperch bodies was also significantly influenced by the dietary lipid content.…”

“…In the case of sea bass, Dicentarchus labrax, a faster growth rate was also noted in fish that received a diet richer in lipids (19% versus 15 or 11%) (Lanari et al, 1999). Jobling et al (1998) did not observe that the dietary lipid levels had a significant effect on the amount of consumed feed or on the weight gains of juvenile rainbow trout, Oncorhynchus mykiss (BW ≈ 90 g), which received feed with either high or low lipid contents (27.5 versus 12.6%). Likewise, did not find that the dietary lipid content had an effect on the whitefish Coregonus lavaretus Table 3.…”

Preliminary Evaluation of Rainbow Trout Diets Containing PepSoyGen, a Fermented Soybean Meal Product, and Additional Amino Acids

“…In the current study, no differences in VSI occurred among the diets. The lack of difference in VSI may be due to the similar lipid levels among the diets, given the positive relationship between dietary lipid and VSI [62][63][64]. It could also be due to the small sample sizes used in this study.…”

High levels of dietary fat impair glucose homeostasis in rainbow trout

“…Additionally, long-term palmitate feeding has been reported to induce hyperinsulinaemia, hyperglycaemia and loss of insulin sensitivity in the omnivorous Indian perch (Anabas testudineus), classic symptoms of the development of insulin resistance in mammals (Barma et al, 2006), suggesting that the mechanisms mediating the control and possible disturbance of glucose homeostasis are beingdigestible carbohydrate (Fernández et al, 2007;Kaushik and OlivaTeles, 1985;Venou et al, 2003) content as non-protein energy sources in order to spare protein for growth and reduce nitrogen loss to the aquatic environment. The positive protein-sparing effects of increased dietary lipid and digestible carbohydrate are, however, often associated with adverse effects in terms of fat deposition (Company et al, 1999;Jobling et al, 1998) and with the development of IGT in fish (Bergot, 1979;Cheng et al, 2006;Hutchins et al, 1998;Polakof et al, 2010).…”