Papers by Sadasivam Kaushik
The British journal of nutrition, Jan 20, 2015
Se is an essential micronutrient required for normal growth, development and antioxidant defence.... more Se is an essential micronutrient required for normal growth, development and antioxidant defence. The objective of the present study was to assess the impact of dietary Se sources and levels on the antioxidant status of rainbow trout (Oncorhynchus mykiss) fry. First-feeding fry (initial body weight: 91 mg) were fed either a plant- or fishmeal-based diet containing 0·5 or 1·2 mg Se/kg diet supplemented or not with 0·3 mg Se/kg diet supplied as Se-enriched yeast or sodium selenite for 12 weeks at 17°C. Growth and survival of rainbow trout fry were not significantly affected by dietary Se sources and levels. Whole-body Se was raised by both Se sources and to a greater extent by Se-yeast. The reduced:oxidised glutathione ratio was raised by Se-yeast, whereas other lipid peroxidation markers were not affected by dietary Se. Whole-body Se-dependent glutathione peroxidase (GPX) activity was enhanced in fish fed Se-yeast compared to fish fed sodium selenite or non-supplemented diets. Activi...
Archiv für Tierernaehrung, 1996
Two trials were conducted with duplicate groups of (first feeding) carp larvae fed artificial dry... more Two trials were conducted with duplicate groups of (first feeding) carp larvae fed artificial dry diets based on casein and dextrin over 21 or 25 days. One control diet based on yeast was also tested. Survival, growth and fatty acid profiles of larvae were studied.In trial 1, (n‐3) fatty acid requirement was estimated using diets supplemented or not with methyl
Reproduction Nutrition Development, 1998
Fish physiology and biochemistry, 2015
Mineral needs as affected by changes in dietary protein and oil sources were studied in rainbow t... more Mineral needs as affected by changes in dietary protein and oil sources were studied in rainbow trout. Duplicate groups (n = 30 fish per replicate) of rainbow trout (initial BW: 37 g) were fed either a fish meal/fish oil-based (M) or a complete plant ingredient (V)-based diet at four graded ration (R) levels [apparent satiation (AS), R75, R50 and R25 % of AS]; one treatment group was maintained under starvation. The feeding trial lasted 12 weeks at a water temperature of 17 °C. Dietary intake, apparent digestibility and initial and final whole-body composition data were used to calculate mineral gain which was regressed against digestible mineral intake (both expressed as mg or µg kg(-0.8) day(-1)). Starvation loss (SL), endogenous loss of fed fish (ELF, y-intercept at x = 0) and point of intake for zero balance (PZB, x-intercept at y = 0) were used as estimates of maintenance requirements. SL provided the lowest estimate, ELF provided the net requirement of a mineral for maintenanc...
Communications in agricultural and applied biological sciences, 2013
Sustainable aquaculture, which entails proportional replacement of fish-based feed sources by pla... more Sustainable aquaculture, which entails proportional replacement of fish-based feed sources by plant-based ingredients, is impeded by the poor growth response frequently seen in fish fed high levels of plant ingredients. This study explores the potential to improve, by means of early nutritional exposure, the growth of fish fed plant-based feed. Rainbow trout swimup fry were fed for 3 weeks either a plant-based diet (diet V, V-fish) or a diet containing fishmeal and fish oil as protein and fat source (diet M, M-fish). After this 3-wk nutritional history period, all V-or M-fish received diet M for a 7-month intermediate growth phase. Both groups were then challenged by feeding diet V for 25 days during which voluntary feed intake, growth, and nutrient utilisation were monitored (V-challenge). Three isogenic rainbow trout lines were used for evaluating possible family effects. The results of the V-challenge showed a 42% higher growth rate (P = 0.002) and 30% higher feed intake (P = 0.005) in fish of nutritional history V compared to M (averaged over the three families). Besides the effects on feed intake, V-fish utilized diet V more efficiently than M-fish, as reflected by the on average 18% higher feed efficiency (P = 0.003). We noted a significant family effect for the above parameters (P,0.001), but the nutritional history effect was consistent for all three families (no interaction effect, P.0.05). In summary, our study shows that an early shortterm exposure of rainbow trout fry to a plant-based diet improves acceptance and utilization of the same diet when given at later life stages. This positive response is encouraging as a potential strategy to improve the use of plant-based feed in fish, of interest in the field of fish farming and animal nutrition in general. Future work needs to determine the persistency of this positive early feeding effect and the underlying mechanisms.
Communications in agricultural and applied biological sciences, 2013
Se is an essential micronutrient required for normal growth, development and antioxidant defence.... more Se is an essential micronutrient required for normal growth, development and antioxidant defence. The objective of the present study was to assess the impact of dietary Se sources and levels on the antioxidant status of rainbow trout (Oncorhynchus mykiss) fry. First-feeding fry (initial body weight: 91 mg) were fed either a plant- or fishmeal-based diet containing 0·5 or 1·2 mg Se/kg diet supplemented or not with 0·3 mg Se/kg diet supplied as Se-enriched yeast or sodium selenite for 12 weeks at 17°C. Growth and survival of rainbow trout fry were not significantly affected by dietary Se sources and levels. Whole-body Se was raised by both Se sources and to a greater extent by Se-yeast. The reduced:oxidised glutathione ratio was raised by Se-yeast, whereas other lipid peroxidation markers were not affected by dietary Se. Whole-body Se-dependent glutathione peroxidase (GPX) activity was enhanced in fish fed Se-yeast compared to fish fed sodium selenite or non-supplemented diets. Activity and gene expression of this enzyme as well as gene expression of selenoprotein P (SelP) were reduced in fish fed the non-supplemented plant-based diet. Catalase, glutamate-cysteine ligase and nuclear factor-erythroid 2-related factor 2 (Nrf2) gene expressions were reduced by Se-yeast. These results suggest the necessity to supplement plant-based diets with Se for rainbow trout fry, and highlight the superiority of organic form of Se to fulfil the dietary Se requirement and sustain the antioxidant status of fish. GPX and SelP expression proved to be good markers of Se status in fish.
The Journal of nutrition, 2008
In mammals, the ubiquitin-proteasome proteolytic pathway is a major route of protein degradation ... more In mammals, the ubiquitin-proteasome proteolytic pathway is a major route of protein degradation and has been shown to be regulated by the feeding status via the protein kinase B (PKB)-Forkehead box-O transcription factor signaling pathway-mediated transcription regulation of atrophy-related ubiquitin ligases, atrogin1 and muscle RING finger 1. In contrast, in rainbow trout (Oncorhynchus mykiss), the activity of the proteasome in muscle was not affected during starvation-induced muscle degradation. The aim of this study was therefore to explore the molecular basis for this lack of induction of this proteolytic route during starvation. In this study, rainbow trout were food deprived for 7 and 14 d, refed ad libitum, and the effect of the nutritional status was assessed on the different steps involved in the regulation of the ubiquitin-proteasome system in muscle. We observed that starvation reduced the phosphorylation of PKB and enhanced the expression of atrogin1 in muscle, whereas ...
Reproduction, nutrition, development
Four diets with differing lipid contents (15, 20, 25 or 30% DM) were tested on small (initial bod... more Four diets with differing lipid contents (15, 20, 25 or 30% DM) were tested on small (initial body weight: 27 g) and larger (IBW: 93 g) rainbow trout (Oncorhynchus mykiss) fed on demand or by hand, respectively. In both trials, voluntary feed intake was inversely related to dietary lipid levels. Protein efficiency increased when dietary fat content increased. Final whole-body lipid content was positively related to dietary lipid levels. The main sites of lipid storage were visceral adipose tissue and to a lesser extent muscle. Increased fat deposition in the visceral cavity of young trout was due to both hyperplasic and hypertrophic responses and in larger trout mostly due to a hypertrophic response. Liver activities of glucose-6-phosphate dehydrogenase and fatty acid synthetase were negatively correlated with fat intake and positively with starch intake, whereas malic enzyme was little affected by dietary treatments.
The Journal of experimental biology, 2001
Rainbow trout (Oncorhynchus mykiss) are known to use dietary carbohydrates poorly. One of the hyp... more Rainbow trout (Oncorhynchus mykiss) are known to use dietary carbohydrates poorly. One of the hypotheses to explain the poor utilisation of dietary glucose by these fish is a dysfunction in nutritional regulation of hepatic glucose metabolism. In this study, we obtained partial clones of rainbow trout cDNAs coding for a glucose transporter (Glut2), and for the enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (6PF-2K/F-2,6BPase), fructose-1,6-bisphosphatase (FBPase) and pyruvate kinase (PK). Their deduced amino acid sequences were highly similar to those of mammals (up to 80% similarity). In a study of nutritional regulation, the Glut2 gene was highly expressed in the liver irrespective of the nutritional status of the trout, in agreement with the role of this transporter in the input (during refeeding) and output (during fasting) of glucose from the liver. Moreover, whereas PK and FBPase gene expression was high irrespective of the nutritional status, levels of hepatic 6...
Journal of animal science, 1999
Our objectives were to test the potential replacement of fish meal by soy protein concentrate (SP... more Our objectives were to test the potential replacement of fish meal by soy protein concentrate (SPC) in high-energy, extruded diets fed to rainbow trout (Oncorhynchus mykiss) and to evaluate the efficiency of DL-methionine supplementation of soy-based diets. Groups of trout (initial BW 103 to 106 g) were fed to visual satiety with isonitrogenous (6.6% DM) high-energy (22.8 MJ/kg DM gross energy), extruded diets, in which fish meal was progressively replaced with SPC (0, 50, 75, and 100%). Three 100% SPC diets were formulated to be either unsupplemented or supplemented with DL-methionine, so that total methionine content was .8 or 1.0% of DM. The quality of the SPC source used was assessed by measuring the antitryptic and antigenic activities and the concentrations of the isoflavones daidzein and genistein. Apparent digestibility of the diets was determined using the indirect method. A growth trial was conducted over 90 d at a water temperature of 18 degrees C. In addition to body com...
Two rapeseed meals (RM1 and RM2), containing glucosinolates at a concentration of 26 and 40 mol/g... more Two rapeseed meals (RM1 and RM2), containing glucosinolates at a concentration of 26 and 40 mol/g, respectively, were incorporated at increasing levels (10, 20, and 30% for RM1 and 30 and 50% for RM2) in diets of juvenile rainbow trout. Disturbances in the thyroid axis appeared after 14 days of feeding (with a dietary incorporation level of 10%). The dietary supplementation with T 3 or iodine induced an increase in plasma T 3 levels, compared to that in fish fed the RM diets, and reduced the deleterious effect of RM on growth. When trout were reared in seawater, there was also a slight increase in thyroid hormone levels. TSH treatment had no effect on the thyroid hormone plasma levels. The incorporation of 30% of RM1, which induced a lower dietary content of toxic compounds than RM2, led to a rapid decrease of plasma T 4 and T 3 levels, but growth was affected only after 6 months of feeding. During these studies, the deiodinase activities responded in a complex manner to restore plasma and tissue levels of T 3 .
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Papers by Sadasivam Kaushik