Dominique Bureau | University of Guelph (original) (raw)
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Papers by Dominique Bureau
J Fish Biol, 2007
ABSTRACT The study examined whether the early life-history temperature experience of rainbow trou... more ABSTRACT The study examined whether the early life-history temperature experience of rainbow trout Oncorhynchus mykiss embryos affects subsequent growth and expression of growth-related genes in the growing-up juveniles in response to variations in ration levels. Embryos were reared in a Heath incubator at either 8·5° C (E8·5) or 6·0° C (E6·0) until hatching, at which time they were transferred to grow-up tanks supplied with water at 8·5° C. At swim-up, the late stage embryos were subsequently fed a salmonid starter diet at levels of 5, 2 or 0·5% of live body mass per day. The body mass and proximate composition of the juveniles was examined when yolk absorbance was complete (21 days after the fish commenced feeding). Quantitative RT-PCR was used to examine the expression of mRNA encoding for growth hormone receptors 1 and 2 (GHR1 and GHR2) in the liver, and the two isoforms of thyroid hormone receptor (TRα and TRβ) in the liver and intestinal tract. Final body mass and total length, liver and intestinal masses, and total lipid content of the E8·5 treatment group were directly related to increased ration size. These variables in the E6·0 treatment group fed the 5% ration were significantly lower than for the comparable E8·5 treatment group, suggesting an effect of embryo rearing temperature on the subsequent growth of these late stage embryos as they undergo the transition from embryo to early juvenile. Intestinal TRα and TRβ mRNA abundance was directly related to ration size in the E8·5 treatment group, but not in the E6·0 treatment group. Conversely, hepatic TRα and TRβ mRNA abundance was significantly affected by ration size only in the E6·0 group, with TRβ and TRα abundance showing direct and inverse relationships with ration size, respectively. Hepatic GHR1 mRNA abundance was significantly and directly related to ration size in both the E8·5 and E6·0 treatment groups, but there were no differences in the abundance of hepatic GHR2 mRNA among any treatments.
![Research paper thumbnail of The partitioning of energy from digestible carbohydrates by rainbow trout, Oncorhynchus mykiss [microform]](https://attachments.academia-assets.com/41482582/thumbnails/1.jpg)
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Feeding and Digestive Functions in Fishes, 2008
A growth trial was conducted to determine relative bioavailability between two commercially avail... more A growth trial was conducted to determine relative bioavailability between two commercially available sources of supplemental lysine in rainbow trout. A basal diet, which was formulated to be deficient in lysine while meeting all other known nutritional requirements for rainbow trout was supplemented with increasing levels (0.1, 0.2, 0.4 & 0.6%) of l-lysine on an equimolar basis from one of two supplemental lysine sources; l-lysine sulfate (Bio-lys) or l-lysine HCl. Diets were fed in triplicate to groups of rainbow trout (IBW = 25 ± 0.6 g) for 12 weeks using a pair-feeding protocol. Fish which received diets containing supplemental lysine from either source exhibited improved weight gain (p < 0.05), growth rate (p < 0.05), retained nitrogen (p < 0.05), retained nitrogen efficiency (p < 0.05) and feed efficiency (p < 0.01) compared to fish which received the unsupplemented basal diet. Similarly increasing levels of lysine supplementation from either source resulted in ...
The feed industry is relying more on economical feedstuffs while formulating feeds to lower the e... more The feed industry is relying more on economical feedstuffs while formulating feeds to lower the existing nutritional specifications. These new strategies are leading feed manufacturers to explore and utilize novel approaches for better nutrient availability in feeds. Exogenous protease enzymes have been shown to improve protein digestibility and feed efficiency using in-vivo studies in both poultry and swine. There is a need for practical in-vitro techniques as current techniques such as enzyme kinetic assays are problematic and in-vivo trials are costly and labourious. The main objectives of this study was to develop and compare two in-vitro techniques, the HCl-Pepsin protein digestibility and the total soluble amino acid methods, that are able to differentiate between control diets and diets containing a protease enzyme (Jefo Nutrition Inc., Canada). > Two in-vitro techniques were developed to evaluate nutritive value of commercially pelleted shrimp diets (containing 0, 175 and...
Molecular Reproduction and Development
Journal of Applied Ichthyology, 2014
Aquaculture Economics & Management, 2007
Fisheries Science
Accurate prediction of proximate composition for a commercially cultured fish at a particular bod... more Accurate prediction of proximate composition for a commercially cultured fish at a particular body weight could help to reduce overall feed waste, improve feed efficiency, and increase profitability. We studied the relationship between biochemical composition of Nile tilapia and its wet weight for the range of minimum and maximum body weight found in the published literature. We also tested the predictive value of regression equations. Logarithmic trends of the proximate composition showed a linear trend for tilapia up to 0.4 g. The trend formed a plateau for tilapia larger than 5 g. The slopes (b) for water, protein, fat, and ash contents as percent body-weight were -0.008, 0.003, 0.003, and 0.002 respectively. The slopes were close to “0” and did not change significantly after removing data from fishes smaller than 5 g in all four cases. Mean percent error of water (-0.145) and protein (-0.769) showed no differences between them. A large percent error mean for fat (-39.179) sugges...
Journal of fish diseases, Jan 27, 2014
Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for... more Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for 4 weeks followed by experimental infection (intraperitoneal) with Flavobacterium psychrophilum (4.1 × 10(6) colony-forming units [CFU] mL(-1) ). Mortality of rainbow trout fed either 6.4 mg kg(-1) DON or trout pair-fed the control diet was significantly reduced (P < 0.05) in comparison with trout fed the control diet to apparent satiation (<0.1 mg kg(-1) DON). In a second experiment, trout were fed one of three experimental diets; a control diet, a diet produced with corn naturally contaminated with DON (3.3 mg kg(-1) DON) or a diet containing purified DON (3.8 mg kg(-1) ); however, these fish were not experimentally infected. The presence of DON resulted in significant reduction (P < 0.0001) in feed intake as well as weight gain after 4 weeks. Respiratory burst of head-kidney leucocytes isolated from rainbow trout fed diets containing purified DON (3.8 mg kg(-1) ) was signific...
Journal of animal science, 2005
A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout an... more A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout and Atlantic salmon. Fish were hand-fed to satiation one of four isoenergetic diets (DE = 20 MJ/kg, as-fed basis) with different digestible protein (DP) to DE ratios (24, 22, 20, and 18 g/MJ). Intake of ME (kJ/d), energy deposited as protein (PD, kJ/d), and energy deposited as lipid (LD, kJ/d) were determined by a comparative slaughter technique. Data were analyzed by a factorial approach or by multivariate analysis of PD and LD on ME. Maintenance energy requirements (ME(m)) and efficiency of ME utilization for PD (k(p)) and LD (k(f)) were estimated with both approaches. For the multivariate analysis, an additional parameter, the fraction of ME intake above maintenance used for PD (X) was defined as linear function of BW, with slope (d) and intercept (c) estimated simultaneously with the above parameters. Estimates were highly dependent on the approach and assumptions used. The ME(m) and k...
Nutrient digestion and utilization in farm animals: modelling approaches, 2006
Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of fre... more Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of freshwater aquaculture operations. A dynamic model was constructed to simulate P utilization in salmonid fish through digestion, body deposition and excretion into urine and ...
J Fish Biol, 2007
ABSTRACT The study examined whether the early life-history temperature experience of rainbow trou... more ABSTRACT The study examined whether the early life-history temperature experience of rainbow trout Oncorhynchus mykiss embryos affects subsequent growth and expression of growth-related genes in the growing-up juveniles in response to variations in ration levels. Embryos were reared in a Heath incubator at either 8·5° C (E8·5) or 6·0° C (E6·0) until hatching, at which time they were transferred to grow-up tanks supplied with water at 8·5° C. At swim-up, the late stage embryos were subsequently fed a salmonid starter diet at levels of 5, 2 or 0·5% of live body mass per day. The body mass and proximate composition of the juveniles was examined when yolk absorbance was complete (21 days after the fish commenced feeding). Quantitative RT-PCR was used to examine the expression of mRNA encoding for growth hormone receptors 1 and 2 (GHR1 and GHR2) in the liver, and the two isoforms of thyroid hormone receptor (TRα and TRβ) in the liver and intestinal tract. Final body mass and total length, liver and intestinal masses, and total lipid content of the E8·5 treatment group were directly related to increased ration size. These variables in the E6·0 treatment group fed the 5% ration were significantly lower than for the comparable E8·5 treatment group, suggesting an effect of embryo rearing temperature on the subsequent growth of these late stage embryos as they undergo the transition from embryo to early juvenile. Intestinal TRα and TRβ mRNA abundance was directly related to ration size in the E8·5 treatment group, but not in the E6·0 treatment group. Conversely, hepatic TRα and TRβ mRNA abundance was significantly affected by ration size only in the E6·0 group, with TRβ and TRα abundance showing direct and inverse relationships with ration size, respectively. Hepatic GHR1 mRNA abundance was significantly and directly related to ration size in both the E8·5 and E6·0 treatment groups, but there were no differences in the abundance of hepatic GHR2 mRNA among any treatments.
Feeding and Digestive Functions in Fishes, 2008
A growth trial was conducted to determine relative bioavailability between two commercially avail... more A growth trial was conducted to determine relative bioavailability between two commercially available sources of supplemental lysine in rainbow trout. A basal diet, which was formulated to be deficient in lysine while meeting all other known nutritional requirements for rainbow trout was supplemented with increasing levels (0.1, 0.2, 0.4 & 0.6%) of l-lysine on an equimolar basis from one of two supplemental lysine sources; l-lysine sulfate (Bio-lys) or l-lysine HCl. Diets were fed in triplicate to groups of rainbow trout (IBW = 25 ± 0.6 g) for 12 weeks using a pair-feeding protocol. Fish which received diets containing supplemental lysine from either source exhibited improved weight gain (p < 0.05), growth rate (p < 0.05), retained nitrogen (p < 0.05), retained nitrogen efficiency (p < 0.05) and feed efficiency (p < 0.01) compared to fish which received the unsupplemented basal diet. Similarly increasing levels of lysine supplementation from either source resulted in ...
The feed industry is relying more on economical feedstuffs while formulating feeds to lower the e... more The feed industry is relying more on economical feedstuffs while formulating feeds to lower the existing nutritional specifications. These new strategies are leading feed manufacturers to explore and utilize novel approaches for better nutrient availability in feeds. Exogenous protease enzymes have been shown to improve protein digestibility and feed efficiency using in-vivo studies in both poultry and swine. There is a need for practical in-vitro techniques as current techniques such as enzyme kinetic assays are problematic and in-vivo trials are costly and labourious. The main objectives of this study was to develop and compare two in-vitro techniques, the HCl-Pepsin protein digestibility and the total soluble amino acid methods, that are able to differentiate between control diets and diets containing a protease enzyme (Jefo Nutrition Inc., Canada). > Two in-vitro techniques were developed to evaluate nutritive value of commercially pelleted shrimp diets (containing 0, 175 and...
Molecular Reproduction and Development
Journal of Applied Ichthyology, 2014
Aquaculture Economics & Management, 2007
Fisheries Science
Accurate prediction of proximate composition for a commercially cultured fish at a particular bod... more Accurate prediction of proximate composition for a commercially cultured fish at a particular body weight could help to reduce overall feed waste, improve feed efficiency, and increase profitability. We studied the relationship between biochemical composition of Nile tilapia and its wet weight for the range of minimum and maximum body weight found in the published literature. We also tested the predictive value of regression equations. Logarithmic trends of the proximate composition showed a linear trend for tilapia up to 0.4 g. The trend formed a plateau for tilapia larger than 5 g. The slopes (b) for water, protein, fat, and ash contents as percent body-weight were -0.008, 0.003, 0.003, and 0.002 respectively. The slopes were close to “0” and did not change significantly after removing data from fishes smaller than 5 g in all four cases. Mean percent error of water (-0.145) and protein (-0.769) showed no differences between them. A large percent error mean for fat (-39.179) sugges...
Journal of fish diseases, Jan 27, 2014
Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for... more Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for 4 weeks followed by experimental infection (intraperitoneal) with Flavobacterium psychrophilum (4.1 × 10(6) colony-forming units [CFU] mL(-1) ). Mortality of rainbow trout fed either 6.4 mg kg(-1) DON or trout pair-fed the control diet was significantly reduced (P < 0.05) in comparison with trout fed the control diet to apparent satiation (<0.1 mg kg(-1) DON). In a second experiment, trout were fed one of three experimental diets; a control diet, a diet produced with corn naturally contaminated with DON (3.3 mg kg(-1) DON) or a diet containing purified DON (3.8 mg kg(-1) ); however, these fish were not experimentally infected. The presence of DON resulted in significant reduction (P < 0.0001) in feed intake as well as weight gain after 4 weeks. Respiratory burst of head-kidney leucocytes isolated from rainbow trout fed diets containing purified DON (3.8 mg kg(-1) ) was signific...
Journal of animal science, 2005
A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout an... more A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout and Atlantic salmon. Fish were hand-fed to satiation one of four isoenergetic diets (DE = 20 MJ/kg, as-fed basis) with different digestible protein (DP) to DE ratios (24, 22, 20, and 18 g/MJ). Intake of ME (kJ/d), energy deposited as protein (PD, kJ/d), and energy deposited as lipid (LD, kJ/d) were determined by a comparative slaughter technique. Data were analyzed by a factorial approach or by multivariate analysis of PD and LD on ME. Maintenance energy requirements (ME(m)) and efficiency of ME utilization for PD (k(p)) and LD (k(f)) were estimated with both approaches. For the multivariate analysis, an additional parameter, the fraction of ME intake above maintenance used for PD (X) was defined as linear function of BW, with slope (d) and intercept (c) estimated simultaneously with the above parameters. Estimates were highly dependent on the approach and assumptions used. The ME(m) and k...
Nutrient digestion and utilization in farm animals: modelling approaches, 2006
Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of fre... more Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of freshwater aquaculture operations. A dynamic model was constructed to simulate P utilization in salmonid fish through digestion, body deposition and excretion into urine and ...