Dietary Amino Acid Balance Research Articles

Self-selection of feeds and water by swine during pregnancy and lactation.

THE technique of self-selection of feeds was used extensively by Richter and Barelare (1938) to show that the feed intake of rats could be reduced by about 20% during pregnancy and almost 50% in lactation compared with a regimen in which rats were fed a complete, stock diet. The smaller feed intake was thought due to a satisfaction of specific needs without an obligation to ingest large amounts of other, unneeded nutrients. Evvard (1914) originated the “free-choice” system of feeding pigs based on corn, protein supplement (meat meal) and minerals. Recently, Owen and Ridgman (1968) demonstrated the development of a compensatory response by pigs fed low energy diets which resulted in similar digestible energy intakes, and Henry and Rerat (1968) reported that, similarly to the rat, the pig adjusts its energy intake according to protein intake, or more precisely, to the gain of weight allowed by the protein intake. Devilat et al. (1969) have shown that pigs can preferentially select an amino-acid balanced diet.

Dietary Amino Acid Balance in Growing-Finishing Pigs: Effect on Diet Preference and Performance1

The effect of dietary amino acid balance upon diet preference and performance of individually-fed pigs was studied in three experiments. A complete diet (A), an incomplete diet (deficient in several amino acids) (B) and a protein-free diet (C) were offered in four free-choice treatments: AA, AB, AC and BC choices. Pigs preferred the A diet in the AB choice (93.5 and 88.6%) and in the AC choice (69.1 and 63.1%) during the growing and finishing periods, respectively. Weight gain, feed intake and serum protein concentration were depressed only in the BC choice. The AC choice produced fatter carcasses than AA and AB choices. Pigs given the BC choice selected B diet 39.7 and 47.0% during growing and finishing periods, respectively. By replacing B by A diet in the choice growth-depressing effects were overcome but loin eye area remained smaller than in pigs in AA and AB. With finishing pigs using the same four treatments, results were similar to those with growing pigs except that in BC choice gain was less severely depressed, feed intake was not depressed and selection of B diet (61.2%) was greater, indicating that age has an effect on the acceptance of an amino acid imbalanced diet. It is concluded that: (1) pigs prefer an amino acid balanced diet to a diet of a similar protein level but with a deficiency of several amino acids, (2) choice between a protein-free diet and an adequate protein diet results in intake of sufficient protein for maximum weight gain but not for maximum carcass leanness, (3) growing pigs prefer a protein-free diet (which will not support life) to an incomplete protein with a deficiency of several amino acids (which will support life); finishing pigs appear to be less selective.

The Interaction Between Dietary Calcium and Protein for Laying Hens

A GREAT deal of information is available on the calcium requirement of the laying hen. Much of the recent work in this field has been reviewed by Mehring (1965) and although there are some differences of opinion most workers are in agreement that a dietary calcium level of 2.5–4.0 percent is required for egg production-type birds depending on the conditions. There are also many reports in the literature concerning the protein requirement, and the factors influencing the protein requirement of laying hens. Differences in protein requirements due to strain have been reported by Harms and Waldroup (1962), age and environmental temperature by Reid et al. (1965), dietary amino acid balance by Bray (1965), and dietary energy level by Lillie and Denton (1965). It is apparent that any factor which influences feed intake will affect the requirement of layers for protein and calcium when the requirements are expressed as a …

Effect of Dietary Amino Acid Balance on the Excretion of Urinary N Compounds and their Ratios

When weanling male rats were fed amino acid diets which were gradedly varied tryptophan level only (0.18, 0.09 and 0.06%), allantoin and urea excretions were determined, and (allantoin/urea) × protein intake values were calculated. (Allantoin/urea) × protein intake values almost linearly increased with the increment of tryptophan level of the amino acid mixture. From these data, it was assumed that one of the main factors affecting these ratios is in amino acid balance in diet. It was also found that the equivalent weight gains observed between 0.18 and 0.09% Try. groups were mainly due to body fat accumulation of the latter.

Effect of Dietary Amino Acid Balance on the Excretion of Urinary N Compounds and their Ratios

When weanling male rats were fed amino acid diets which were gradedly varied tryptophan level only (0.18, 0.09 and 0.06%), allantoin and urea excretions were determined, and (allantoin/urea) × protein intake values were calculated. (Allantoin/urea) × protein intake values almost linearly increased with the increment of tryptophan level of the amino acid mixture. From these data, it was assumed that one of the main factors affecting these ratios is in amino acid balance in diet. It was also found that the equivalent weight gains observed between 0.18 and 0.09% Try. groups were mainly due to body fat accumulation of the latter.

Control of Egg Size in Chickens through Dietary Amino-acid Balance

THERE are conflicting reports regarding the influence of the level of protein and of specific amino-acids in the diet of the hen on egg size. Results from an experiment in this laboratory suggested that the balance, rather than absolute levels, of amino-acids determines the response to different amounts of dietary protein and to amino-acid supplementation of the laying diet. There was also evidence that egg size may be modified quickly by altering dietary amino-acid balance. The following experiment was designed to test the validity of these observations.

Observations on the Influence of Dietary Protein Level and Amino Acid Balance on Pigmentation in the Feathers of Chicks ,

KLAIN et al. (1957) observed the development of a severe feather achromatosis in Barred Plymouth Rock cockerels fed a lysine-deficient diet. The diet used in these experiments supplied all the essential amino acids in apparently adequate quantities for normal growth with the exception of lysine.An evident question which arose from these results, therefore, was whether the low lysine intake in itself was the major factor involved in the deficiency of feather color, or, primarily, whether an unbalanced intake with respect to lysine and other amino acids was concerned.In order to investigate this problem a series of experiments was undertaken using a diet in which the protein level could be changed without altering the pattern of amino acids being offered.EXPERIMENTALBarred Plymouth Rock cockerels were used in all experiments. They were housed in heated battery brooders and fed the experimental diets ad libitum from day-old to 4 weeks…

Effect of Dietary Amino Acid Balance on Fat Deposition in the Livers of Rats Fed Low Protein Diets

Effect of Dietary Amino Acid Balance on Fat Deposition in the Livers of Rats Fed Low Protein Diets

Effect of Single Amino Acid Excesses on Glucose Metabolism and Chick Growth, as Influenced by the Dietary Amino Acid Balance

Effect of Single Amino Acid Excesses on Glucose Metabolism and Chick Growth, as Influenced by the Dietary Amino Acid Balance