Determination of Nutritional Requirements in Rats: Variation with Time of Weight Gain Responses to Indispensable Amino Acids

Mercer, L. Preston; Yi, Tang; Dodds, Steven J.

doi:10.1093/jn/123.5.964

Cited by 8 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It appears that an additional source of variation was in¯uencing the response. A similar problem was observed with another data set (Olivera-Novoa et al 1996). Residual analysis and outlier detection should be performed.…”

Section: Data Qualitysupporting

confidence: 53%

“…A similar failure to test alternative models can be seen in another recently published study (Rodehutscord 1996) Time: A component of nutrition studies that has received little attention is the duration of the experiment. Mercer et al (1993) showed that requirement estimates should be considered a response surface, using dietary nutrient level, weight gain and time as the three dimensions rather than a twodimensional relationship (Fig. 9).…”

Section: Broken Linementioning

confidence: 99%

“…Baker (1986) stressed that the choice of statistical method may have a large eect on the estimated value of the requirement. Despite the fact that these authors agreed that regression produces a more accurate estimate than alternative methods of examining the dose±response relationship, neither this technique, nor the newer dose±response models (Mercer et al 1989(Mercer et al , 1993, have been consistently used in ®sh nutrition studies.…”

Section: Introductionmentioning

confidence: 99%

“…A dose±response surface showing weight vs. time of rats fed graded levels of valine. The data are fromMercer et al (1993).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Experimental design, statistical analysis and modelling of dietary nutrient requirement studies for fish: a critical review

Shearer

2000

Aquaculture Nutrition

254

203

View full text Add to dashboard Cite

A limited survey of published reports on dietary nutrient requirement estimates for ®sh (three journals, 46 papers) indicates that broken-line analysis and analysis of variance (ANOVA ANOVA) are often used to estimate nutrient requirements from dose±response data. The application of regression models using published treatment mean values to re-evaluate estimates was possible using 33 of these reports. Re-evaluation suggests that the broken-line method and ANOVA ANOVA frequently underestimate the requirement. Regression produced estimates that averaged approximately twice, but were up to ®ve times the published requirement. Additional problems that prevented re-evaluation or produced errors in the original estimates were: failure to include nutrient levels high enough to produce a maximum response, failure to space nutrient input levels closely enough to adequately model the dose±response relationship, an apparent failure to screen data before analysis, and insucient model diagnosis. Examples from the literature are presented to illustrate how design, method of analysis and the choice of model aect the requirement estimate. The eects of measurement frequency and the experiment duration on the resulting requirement estimate are discussed. A set of protocols is presented to help improve nutrient requirement estimates.KEY WORDS analysis problems are shown and protocols for preventing these problems are presented. The approach taken is conceptual rather than computational, and references discussing pertinent topics in detail are provided to aid in rectifying speci®c problems.

show abstract

Section: Data Qualitysupporting

confidence: 53%

Section: Broken Linementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…A dose±response surface showing weight vs. time of rats fed graded levels of valine. The data are fromMercer et al (1993).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Experimental design, statistical analysis and modelling of dietary nutrient requirement studies for fish: a critical review

Shearer

2000

Aquaculture Nutrition

254

203

View full text Add to dashboard Cite

show abstract

“…For [57,58], the models used to predict the requirements must have biological and mathematical meaning.…”

Section: Amino Acids Methodologies: Requirementmentioning

confidence: 99%

Amino Acid for Japanese Quails: Methodologies and Nutritional Requirement

Vieira¹,

Costa²,

Lima³

et al. 2017

Amino Acid - New Insights and Roles in Plant and Animal

View full text Add to dashboard Cite

The methodologies applied to chickens and laying hens, to determine the digestibility and requirement of protein and amino acids are used with quails, however, they need a more careful evaluation due to peculiarities inherent to the Coturnix genus, in order to provide consistent results. The nutritional requirements of the birds are determinate using the dose-response and the factorial method. Several mathematical models and techniques of diet formulation are allied to the dose-response method in determining nutritional requirements. The curvilinear (hyperbolic) models beter portray population behaviour in response to increasing nutrient doses in diets. The reading model, allow a beter estimation of the requirement, in relation to the mathematical models used in the dose-response method. The techniques of comparative slaughter and nitrogen balance are efective in determining the nutritional requirements of quails, however, the later need to be corrected by the loss of nitrogen in the feathers in determining the requirements of crude protein and amino acids for maintenance. The protein-free diet, coupled with the industrial amino acid supplementation, provides more robust digestibility values, since it more efectively predicts the endogenous excretion patern.

show abstract

Weight gain responses of laying-type pullets to methionine plus cystine intake

Silva

Lima

Sakomura

et al. 2020

Animal

View full text Add to dashboard Cite

Each individual in the population has a distinct maximum growth potential, and the growth curve may vary depending on the response to nutrient intake, growth phase and variability among animals. The present study aimed to (1) model weight gain (WG) response to methionine+cystine (Met+Cys) supply using different mathematical functions, (2) identify functions that better fit the growth responses of pullets, (3) determine the Met+Cys requirements that maximize WG based on breeding standards and (4) partition the Met+Cys requirements for WG and maintenance. Three trials were performed using 1448 laying-type pullets. We adopted a completely randomized design with eight treatments and six replicates. The first trial (2 to 6 weeks, P1) used 15 pullets per experimental unit. The second and third trials (8 to 12 weeks, P2; 14 to 18 weeks, P3) were used eight pullets per replicate. The Met+Cys levels were obtained using a dilution technique. The mathematical functions used to describe WG responses to Met+Cys intake were broken line, broken line with curvilinear ascendancy, Michaelis–Menten, saturation kinetics and three logistic and three exponential models. Models were selected using the Bayesian information criterion and evaluated by residual analysis. It was possible to model the responses using the studied functions. The best functions were obtained by logistic and sigmoidal models in P1 and P2, and with the broken line by the curvilinear ascendancy model in P3. The Met+Cys intake that determined the maximum potential for WG (WGmax) in P1, P2 and P3 were 313, 381 and 318 mg/day, respectively. The Met+Cys requirements for WG were 20, 22 and 27 mg/g, and for maintenance were 214, 53 and 30 mg/kgBW0.75 for P1, P2 and P3, respectively.

show abstract

Determination of Nutritional Requirements in Rats: Variation with Time of Weight Gain Responses to Indispensable Amino Acids

Cited by 8 publications

References 6 publications

Experimental design, statistical analysis and modelling of dietary nutrient requirement studies for fish: a critical review

Experimental design, statistical analysis and modelling of dietary nutrient requirement studies for fish: a critical review

Amino Acid for Japanese Quails: Methodologies and Nutritional Requirement

Weight gain responses of laying-type pullets to methionine plus cystine intake

Contact Info

Product

Resources

About