Query: fish feed intake and energy level

title: The influence of energy level on the feed intake, growth, food conversion and body composition of Sparus aurata
abstract: Sparus aurata of mean weight 43.7 g were fed five diets differing in energy (soybean oil) for three months. Lowest energy diet contained 19,610 J/g and highest 21,140 J/g. Protein and fat contents for the species exceeded the minimum requirements of 40% and 8% respectively. Feed intake and growth were significantly higher for fish on the lower energy (soybean oil) diets. Energy conversion factor was also significantly lower in the lower energy diets. No significant differences in feed or protein and ash conversion factors, protein efficiency ratio, protein productive value and feed conversion efficiency were found. Increases in body protein and fat and energy were significantly higher in the lower energy treatments; however, body composition was not affected by treatment. Significant correlation coefficients between different body components enabled calculation of regression equations by which biologically important parameters, such as protein, fat, ash and energy, can be estimated from a relatively simple moisture determination.

title: Effects of Partial Replacement of Fish Meal Protein by Microalgae on Growth, Feed Intake, and Body Composition of Atlantic Cod
abstract: A feeding trial was conducted with juvenile Atlantic cod Gadus morhua (initial mean weight, 40.7 g) in which a combination of dried Nannochloropsis sp. and Isochrysis sp. replaced fish meal protein in isonitrogenous, isocaloric diets. Three experimental diets (55% protein, 16.5% fat; calculated gross energy 5,328 kcal/kg) were formulated to replace 0, 15, or 30% of dietary fish meal protein. At the conclusion of the 84 d study, no differences in survival, feed conversion ratios, viscerosomatic indices, and n 3 and n 6 fatty acids in the muscle were found among the treatment groups. Feed intake and growth, which were proportional to the level of algal incorporation, were significantly reduced in the algae fed fish and were probably due to palatability problems. Feed intake improved in the fish fed the diet with 15% fish meal protein replacement as the study progressed, but hepatosomatic indices indicate that those fed the diet with 30% replacement were approaching starvation. Received July 13, 2.

title: Effects of dietary starch and energy levels on maximum feed intake, growth and metabolism of Nile tilapia, Oreochromis niloticus
abstract: The aim of this study was to gain insight into how Nile tilapia (Oreochromis niloticus) regulate feed and energy intake in response to diets low and high in starch and cellulose. It was hypothesized that high starch diets would reduce feed intake due to the effect of high blood glucose level, and that stomach volume may limit feed intake of fish fed diets low in energy. Four experimental diets, low starch no cellulose inclusion, high starch no cellulose inclusion, low starch with cellulose inclusion, and high starch with cellulose inclusion, were formulated. The high starch diets and diets with cellulose inclusion were 17.5% more energy diluted than the low starch diets and diets without cellulose inclusion, respectively. Male tilapia were fed to apparent satiation for six weeks. Feed and digestible energy intake of fish fed diets with cellulose inclusion increased and decreased by 8.3% and 5.5% respectively, compared to fish fed diets without cellulose inclusion. This suggests the role of stomach volume in restricting feed consumption. Fish fed high starch diets achieved only 0.5% more feed intake and 13.9% less digestible energy intake than fish fed low starch diets. The lower increase in feed intake and higher decrease in digestible energy intake of fish fed high starch diets than of fish fed diets with cellulose inclusion suggests that high blood glucose suppresses feed intake in Nile tilapia. An alternative explanation for the differences in feed and digestible energy intake of fish fed different diets was based on the fact that heat production was not influenced by starch nor cellulose inclusion levels. Thus, under satiation feeding, oxygen uptake capacity may determine feed and digestible energy intake in fish rather than blood glucose or stomach volume.

title: Regulation of feed intake, growth, nutrient and energy utilisation in European sea bass (Dicentrarchus labrax) fed high fat diets
abstract: Three practical isoproteic (54% protein) diets were formulated to contain graded levels of crude fat (diet L: 10% diet M: 20% and diet H: 30% Each diet was assigned unrestrictedly to three and restrictedly to two replicate groups of fish (IBW 243 g) In unrestricted groups, increasing the dietary lipid level led to a significant decrease in voluntary feed intake without affecting growth rate. In the feed restricted groups, daily growth rates increased with increasing dietary fat levels. There was a significant and inverse effect of the dietary fat content on whole body moisture and fat levels, with highest lipid (ca. 20% and lowest moisture (ca. 58% contents in sea bass fed diet containing the highest lipid level; muscle lipid concentration was however not affected. Nitrogen retention was significantly increased by an increase in lipid concentration in the diets, with better efficiencies observed in unrestricted (ca. 31% than in restricted groups (ca. 27% Nitrogen loss was significantly affected by both the feeding level and the diet composition, with lowest values (ca. 60 g kg 1 in groups fed diet H unrestrictedly and highest values (ca. 90 g kg 1 in groups fed diet L at a restricted level. Soluble phosphorus excretion in H groups was less than half that in L groups, regardless of the feeding level.

title: Regulation of voluntary feed intake in juvenile rainbow trout fed by hand or by self feeders with diets containing two different protein/energy ratios
abstract: The effect of increasing non protein energy level in a 40% protein diet on the voluntary feed intake (VFI) was investigated in juvenile rainbow trout Oncorhynchus mykiss Fish were fed to satiety using two different methods, hand feeding or time restricted self feeding. Regardless of the feeding methods, the VFI ind the feed: gain ratio was always significantly higher for the fish fed the low energy diet than for those fed the high energy diet. In addition, no effect of the diet on the specific growth rate could be detected. It is concluded that fish were able to regulate with a great accuracy their feed intake when fed either by hand or by self feeders. This regulation was precise enough to satisfy their energy needs and led fish fed the two different experimental diets to reach identical growth performance, regardless of the feeding technique.

title: Reduced water oxygen levels affect maximal feed intake, but not protein or energy utilization efficiency of rainbow trout (Oncorhynchus mykiss)
abstract: This study examined the effect of reduced water oxygen levels on the utilization efficiencies of energy and protein from a diet fed to rainbow trout. An experimental diet was fed at one of the four ration levels with an additional starved treatment also included in each oxygenation regime. Oxygen levels in each oxygenation regime varied with ration level, but averaged 9.3 0.36 mg L 1 for the normal regime and 5.7 1.4 mg L 1 for the hypoxia regime. Significant differences were observed in the apparent satietal feed intake levels in each oxygenation regime, but not at any of the pair fed restricted levels. No significant effects of oxygenation regime were observed on the utilization of either energy or protein by the fish. Efficiency of protein use varied depending on the protein intake level, but was not significantly affected by oxygenation regime. This study demonstrates that a reduction in the oxygen levels of the water does not affect the utilization efficiency of dietary digestible protein and energy in rainbow trout, but does result in a downregulation of feed intake when the fish is fed to apparent satietal levels.

title: Compensatory growth in the gibel carp following feed deprivation: temporal patterns in growth, nutrient deposition, feed intake and body composition
abstract: To investigate the nature of compenstory growth in fish, an 8 week study at 28 degreesC was performed on juvenile gibel carp Carassius auratus gibelio weighing 6.6 g. Fish were starved for 0 (control) 1 (Sl)or 2 (S2) weeks and then re fed to satiation For 5 weeks. Weekly changes in weight gain, feed intake and body composition were monitored during re feeding. No significant difference was found in final body weight between the three groups, indicating complete compensation in the deprived fish, The deprived groups caught up in body weight with that of the control after 2 weeks of re feeding. Body fat:lean body mass ratio was restored to the control level within 1 week of re feeding. In the re feeding period, weekly gains in body weight, protein. lipid, ash and energy in the S1 group were significantly higher than in the controls for 1 week. For the S2 group, weekly gains in body weight. lipid. ash and energy were higher than in the controls for 2 weeks, and gain in protein was higher than in the controls for 3 weeks, though gain in body energy became elevated again during the last 2 weeks of the experiment. Feed intake remained higher than the control level for 3 weeks in the S1 group and 3 weeks in the SZ group. Growth efficiency was not significantly different among the three groups in any of the weeks during re feeding. Compensatory responses in growth and especially feed intake tended to last longer than the recovery of body composition.

title: Effect of past nutritional history and fasting on feed intake and growthin rainbow trout Oncorhynchus mykiss
abstract: Groups of juvenile rainbow trout were fed to satiation for 10 days after 1, 11 and 21 days of feed deprivation. These fish (initial body weight 20 2 g) were previously fed at different feeding levels (0.5 or 1.5 initial body weight, to satiation) with a high (20.4 kJ*g 1) or a low (16.2 kJ*g 1) digestible energy diet content for 34 days. It is shown that past nutritional history affected growth performance: duration of feed deprivation has a major effect on intake and feed conversion efficiency; previous feeding level has an effect on intake; dietary energy content affected feed conversion efficiency. In addition, an attempt was made to identify some of the metabolic parameters that could be involved in the increase in growth performance during the 10 day feeding period (whole body and muscle protein and lipid, plasma glucose, free fatty acids and triglycerids) Feed intake after fasting does not appear to be driven by body composition but feed conversion efficiency was correlated with the plasma glucose and free fatty acids.

title: Substitution of fish meal with plant protein sources and energy budget for white shrimp Litopenaeus vannamei (Boone, 1931)
abstract: Fish meal (FM) has long been considered an essential ingredient for the formulation of shrimp feeds. Until recently, 12%FM was considered a minimum amount, below which weight gain would become reduced due to a reduction in feed intake. In order to test this perceived minimum value, an experiment was conducted on a long term basis with 4 replicates. Four practical isonitrogenous and isoenergetic diets were formulated for Litopenaeus vannamei juveniles. Survival, weight gain, feed conversion ratio (FCR) and protein efficiency ratio were determined for 0, 6, 10 and 15% FM diets and a reference diet. Shrimp survival ranged from 84 to 86.5% Shrimp fed a diet with 0% FM showed lower average weight and SGR compared to the other treatments (P 0.05) FCR of shrimp fed the reference diet was significantly lower compared to the other treatments. Short term energy budget did not differ in recovered energy (RE) Variations in RE according to FM level were expected, however, it remained low (0.12 kJ prawn 1 day and it was not possible to discriminate among dietary treatments. Data indicate that RE was similar as evidenced by an absence of difference in weight gain among 6, 10 and 15% FM diets and the reference diet (0.98 g/wk) Growth results obtained over a long term period and in clear water indicated the possibility for FM replacement with soybean plus canola meals.

title: Effects of dietary protein and energy levels on growth, feed utilization and body composition of cuneate drum (Nibea miichthioides)
abstract: An 8 week experiment was conducted in net pens to assess the effects of dietary protein and energy levels on growth, feed utilization and body composition of cuneate drum. Cuneate drum (initial body weight 19 g fish 1 were fed 9 feeds formulated to contain 3 levels of digestible protein (DP 36% 38% and 40% and 3 levels of digestible energy (DE 14, 16 and 18 MJ kg 1 Groups of fish were fed raw fish (Sardinella spp. to serve as a commercial control. Specific growth rate (SGR) final body weight (FBW) feed intake, feed conversion ratio (FCR) energy retention efficiency (ERE) and moisture and protein contents in carcass of the fish were significantly affected by DP and DE levels. Nitrogen retention efficiency (NRE) was dependent on DP level, and lipid and ash contents in carcass of the fish were affected by DE level. Specific growth rate and FBW of fish fed feeds with the same DE level increased when DP increased from 36% to 40% whereas SGR and FBW of fish fed the feeds formulated at the same DP level increased when dietary DE increased from 14 to 16 MJ kg 1 No improvement, or even a slight decline in SGR and FBW, occurred with the further increase of DE to 18 MJ kg 1 For the same DP level, NRE and ERE increased with the increase in DE from 14 to 16 MJ kg 1 Carcass lipid content of fish fed the feeds with the same DP level increased with the increase in DE level. There were no significant differences in SGR, FBW, feed intake, FCR, and protein and lipid contents in carcass of fish fed the raw fish and feed containing 40% DP and 16 MJ kg 1 DE. Nitrogen retention efficiency and ERE were higher for fish fed the formulated feed containing 40% DP and 16 MJ kg 1 DE than fish fed the raw fish.