Improving the estimation of amino acid requirements to maximize nitrogen retention in precision feeding for growing-finishing pigs

Experiments were made to estimate separately the amino acid requirements of growing pigs for maintenance and for protein accretion. The relationship between nitrogen retention and amino acid intake was estimated for each essential amino acid (except histidine) by giving, at rates of N intake of 0.25 and 2.0 g/kg body-weight (W)0.75 per d, diets in which one amino acid was made specifically deficient. From the regression coefficients it was calculated that, for the accretion of 1 g body protein, the dietary amino acid requirements were (mg) threonine 47, valine 53, methionine+cystine 36, methionine 19, isoleucine 43, leucine 78, phenylalanine+tyrosine 84, phenylalanine 41, lysine 68 and tryptophan 12. The daily amino acid requirements for N equilibrium were also estimated. From the relationship between N retention and amino acid intake the daily amino acid requirements for N equilibrium were estimated to be (mg/kg W0.75 per d) threonine 53, valine 20, methionine+cystine 49, methionine 9, isoleucine 16, leucine 23, phenylalanine+tyrosine 37, phenylalanine 18, lysine 36 and tryptophan 11. It was estimated that both for maintenance and for protein accretion tyrosine could provide close to half the total phenylalanine+tyrosine needs. Cystine could supply close to half the total sulphur amino acid needs for protein accretion but 0.8 of the needs for maintenance.

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Methionine plus cystine to lysine ratio in diets for tambatinga fingerlings

Ciência e Agrotecnologia ◽

10.1590/1413-7054202145000721 ◽

2021 ◽

Vol 45 ◽

Author(s):

Dayana da Conceição da Costa ◽

Marcos Antonio Delmondes Bomfim ◽

Felipe Barbosa Ribeiro ◽

Jefferson Costa de Siqueira ◽

Neliane Galvão Porto ◽

...

Keyword(s):

Weight Gain ◽

Amino Acid ◽

Nitrogen Retention ◽

Feed Conversion ◽

Rapid Weight Gain ◽

Retention Efficiency ◽

Body Protein ◽

Protein Deposition ◽

Amino Acid Requirements ◽

Amino Acid Methionine

ABSTRACT Among a variety of hybrids produced in Brazil, tambatinga is obtained from the crossing of a tambaqui female with a pirapitinga male. Although rapid weight gain in less time is an attractive characteristic from a commercial viewpoint, the information on its nutritional requirements, especially amino acid requirements, is limited. As corn and soybean meal-based diets available for fish contain deficient levels of essential amino acid methionine, our objective was to determine the digestible methionine plus cystine to lysine ratio in diets for tambatinga fingerlings. We used 900 fish with initial weights varying from 1.49 ±0.59 to 4.14 ±1.70 g, and they were fed six types of diets with different digestible methionine plus cystine to lysine ratios (50, 55, 60, 65, 70, and 75%). Performance parameters such as food efficiency, body depositions of protein, fat, and ash, and nitrogen retention efficiency were evaluated. The increase of digestible methionine plus cystine to lysine ratio in the diet improved quadraticly the feed intake, consumption of digestible methionine plus cystine, weight gain, specific growth rate and feed conversion, protein deposition and body ash and retention efficiency nitrogen until the estimated ratios of 57%, 73%, 58%, 58% and 59%, 59%, 58% and 60%, respectively; and reduced linearly the efficiency of using methionine plus cystine for the weight gain. On the other hand, body fat deposition was not affected. We concluded that the digestible methionine plus cystine: lysine ratio in the rations for tambatinga fingerlings is 59%, for provide better performance and body protein deposition.

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The isoleucine requirement of the weanling pig

The Journal of Agricultural Science ◽

10.1017/s0021859600013289 ◽

1962 ◽

Vol 58 (3) ◽

pp. 413-422 ◽

Cited By ~ 3

Author(s):

R. E. Evans

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Nitrogen Balance ◽

Essential Amino Acid ◽

Nitrogen Retention ◽

Amino Acid Requirements ◽

Main Criticism ◽

Current Standards

The current standards or estimates of the essential amino acid requirements of swine are based almost wholly on growth trials. These were carried out with groups of three or four pigs fed individually on semisynthetic diets. The trials generally lasted for only 30–35 days since several expensive amino acids were being fed. The main criticism is that the values given were not adequately substantiated by carrying out nitrogen-balance determinations. It is also possible that the nitrogen-retention values might have led to different conclusions from those arrived at on the basis of the growth trials only. The standards must remain tentative until tested with a larger number of animals and until many more nitrogenbalance determinations have been carried out.

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