Influence of dietary fat and carbohydrate levels on growth and body composition of rainbow trout Oncorhynchus mykiss under self-feeding conditions

Abstract

SUMMARY: An 8‐week feeding experiment was conducted to examine the influence of fat and carbohydrate levels in a 40% protein level diet on growth and body composition of rainbow trout Oncorhynchus mykiss under self‐feeding conditions. Five fish meal‐based diets were prepared to include gelatinized potato starch at four levels (9, 18, 27, and 36%) and dextrin (34%). Dietary fat levels were isoenergetically reduced from 18 to 7% by the digestible carbohydrates. Each diet was fed to four replicate groups (28 g/fish, 20–23 fish/group) using self‐feeders. Specific growth rate, percentage weight gain and percentage protein retention did not differ between the treatments. Feed efficiency and protein efficiency ratios were higher in the 18% starch (s18) and s27 diet groups, and decreased in higher fat or carbohydrate diet groups. Although gross energy intake (kJ/kg BW per day) decreased as the starch level increased, levels of digestible energy intake did not differ between the treatments. Fat levels in the carcass, viscera and liver decreased as dietary carbohydrate level increased. These results suggest that a 40% protein diet with either 15% fat and 18% starch or 11% fat and 27% starch is appropriate for juvenile rainbow trout under self‐feeding conditions.

Nutritional and metabolic responses in common dentex (Dentex dentex) fed on different types and levels of carbohydrates

“…Moreover, fish show a reduced ability to digest carbohydrates with high molecular complexity or not pretreated (Peres and Oliva-Teles, 2002;Venou et al, 2003;Enes et al, 2006). Additionally, in general, starch or more simple carbohydrates such as dextrin or maltose (except glucose) digestibility appears to decrease with increasing dietary levels (Hutchins et al, 1998;Skalli, 2001;Yamamoto et al, 2001;Enes et al, 2006). The appropriate dietary inclusion level of digestible carbohydrates has been established between a recommended 20% maximum for carnivorous species, and 40% for hot water omnivorous species (Wilson, 1994;Stone, 2003), although the observed responses for different types and levels of carbohydrates are varied (McMeniman, 2003;Mohapatra et al, 2003;Stone et al, 2003;Enes et al, 2011).…”

Effects of temperature and feeding frequency on ingestion and growth for rare minnow

“…A suitable feeding regime with optimal feeding frequency and temperature not only enhances growth and feeding efficiency of fish, but also minimizes size variations, feed waste, production cost, and disease occurrence [34][35][36][37]. Water temperature and feeding frequency are two important components affecting growth, which have been studied in several fish species such as Channel catfish [38], European seabass [39], rainbow trout [40,41], Tiger Puffer [42], tilapia [24], pikeperch [43], and Asian seabass [44]. Temperature affects food consumption, digestion rate, and growth rate through variations in metabolism [15,45], use of nutrients and energy [18,46], and digestive enzyme activities [17,[47][48][49].…”

Effect of Varying Protein‐to‐Energy Ratios on Growth, Nutrient Retention, Somatic Indices, and Digestive Enzyme Activities of Singhi, Heteropneustes fossilis (Bloch)

“…Because in both these diets 350 Low and 350 High the dietary protein level was much below the requirement of the fish, fish enhanced its feed intake to compensate for this deficiency. Also, diet 450 High contained highly imbalanced levels of 450 g/kg protein and 4.54 kcal/g energy; hence, the reduction in feed intake in fish fed diet 450 High may be due to higher levels of both protein and energy in this diet, and it has been predicted that consumption of a diet is inversely related to its protein and energy content (Yamamoto et al 2001). El‐Dahhar and Lovell (1995) have also reported that excess energy in tilapia diets may have led to a reduced feed consumption.…”