Low-protein Corn-soybean Meal Diet Research Articles

Threonine Requirement of Broiler from 22-42 Days

Threonine is considered to be the third limiting amino acid for broiler chicks fed low protein cornsoybean meal diets. Very limited information is available on the requirement of the threonine for broilers. The aim of this study was to determine the threonine requirements of broiler chickens from 22-42 days of age. Seventy five Ross 308 one-day-old male broiler chicks were divided into five dietary treatment groups of similar mean weight, comprising 15 birds each. They were fed a basal starting diet containing 23% CP, 3200 ME kcal/kg, 0.81% threonine and 1.24% lysine for first 3 weeks. Chicks were randomly assigned to five treatments involving 0.70, 0.75, 0.80, 0.85 and 0.90% of total threonine for 21 days (between 22-42 days). Results indicated that a linear response to dietary threonine for final body weight, body weight gain and threonine intake occurred in experiment but other live performance parameters were not impacted by dietary threonine. Our results suggest that the current NRC recommendation of 0.74% threonine for 3-6 week old broilers is adequate to support comparable growth performance.

Starter Period Digestible Valine Requirement of Female Nicholas Poults

Two experiments were conducted to determine the digestible Valine requirement in female Nicholas poults. A low-protein corn-soybean meal diet with added amino acids was used for the valine titration. Body weight gain and feed conversion responses to increasing dietary valine were measured. In Experiment 1, a wide range of valine levels were fed, with poults that received 0.79% or more digestible valine achieving maximal growth rate and feed efficiency. A narrower titration was used in Experiment 2, in which poults receiving 0.82% digestible valine were significantly heavier than those fed 0.75% or lower levels. The average growth data subjected to broken-line analysis indicated that the digestible valine requirement for maximum body weight gain was 0.82%. These studies indicate that in a corn-soybean meal diet containing 3218 kcal ME/kg, the dietary valine requirement of starting female Nicholas poults, expressed on a digestible basis, is 0.82%.

A low-protein diet for turkey poults

A series of studies was conducted to determine whether a low-protein corn-soybean meal diet would support growth of turkeys similar to that supported by a standard diet. Three treatments administered in a series of experiments included: basal diet with essential amino acids (EAA), NaHCO3, and glutamic acid added at the expense of sucrose to bring the total protein up to 28% (+GLU); basal diet with EAA, NaHCO3, and sucrose added to bring the total protein content to 22% (+SUC); and a 28% crude protein standard diet that meets or exceeds NRC recommendations using intact protein sources (ST). Essential amino acid levels used in the experimental diets were based on an estimated ideal protein ratio for turkeys. The basal diet contained 18.4% intact CP from corn and soybean meal. All treatments were isocaloric with 3,172 to 3,192 kcal/kg. In all trials, the birds receiving +GLU and +SUC had adequate growth and feed:gain responses compared to birds receiving ST. The low protein basal diet with appropriate amino acid supplementation will allow for amino acid titrations to determine digestible amino acid requirements.

Performance and nutrient balance in growing swine fed low-protein diets supplemented with amino acids and potassium.

Five experiments, using 216 barrows and gilts (initial weight 19.9 to 23.7 kg), were conducted to evaluate the effects of improving amino acid balance by supplementing low-protein corn-soybean meal diets with essential amino acids. Three experiments were growth studies lasting approximately 3 wk, and the other two were 4-d metabolism trials. The control diets in each of the experiments were formulated to contain .80% lysine and contained approximately 17% CP. The other diets were formulated from a basal diet containing a 10.9% CP, fortified corn-soybean meal mixture, which included crystalline L-lysine.HCI, L-tryptophan, L-threonine, L-isoleucine, DL-methionine and L-valine to correct amino acid deficiencies. Nonessential N (glutamic acid or urea) also was added to some of the diets to increase the CP equivalent to 12 or 13%. Supplemental K (as a salt of bicarbonate or glutamate) was included in selected diets to increase the K concentration to the same level as that of the control diet. Growth rate of pigs fed the basal diet was similar (P greater than .05) to that of the control diets in only one growth study. Added glutamic acid and urea did not improve either growth rate or N retention. Added K improved K digestibility but did not increase K retention, N retention or growth rate. Improving amino acid balance by adding essential amino acids to low-protein diets did not benefit performance beyond that of a typical corn-soybean meal diet. Under our conditions, K, N, and nonessential N were not limiting.

Limiting Amino Acids in Low-Protein Corn-Soybean Meal Diets Fed to Growing Chicks

Four trials were conducted with 8-day-old crossbred chicks to determine the limiting amino acids (AA) in a low-protein corn-soybean meal diet. Trials were conducted for either 8 or 14 days. In Trial 1, chicks were fed a 16% crude protein (CP) diet with individual or combined additions of DL-methionine (Met), L-arginine (Arg), L-lysine (Lys), L-threonine (Thr) and L-tryptophan (Trp). Methionine and Arg increased gain considerably, with only a small added response occurring from Lys supplementation. A subsequent addition trial with a 16% CP diet fortified with 3% glutamic acid (Glu) revealed Met to be first limiting, Arg and Lys to be equally second limiting, and valine (Val) and Thr to be equally third limiting. Trial 2 was a deletion study in which eight essential AA were added to the 16% CP diet to provide levels of these AA equal to those present in a 24% CP corn-soybean meal diet. Deletions of Arg, Met, Lys, or Val from the AA-supplemented diet reduced gain 28, 19, 13, and 7%, respectively. In Trial 3, rate and efficiency of gain were increased by addition of 3% Glu to the 16% CP diet containing the full complement of essential AA. Gain of chicks fed this diet, however, still fell somewhat short of that occurring with the 24% CP diet. A second deletion study was employed in the final trial, wherein individual AA deletions were made from the 16% CP diet that had been supplemented with eight essential AA and Glu. Deletions of Met and Lys produced growth depressions of approximately 18%, and deletions of Arg, Val and Thr produced depressions of about 8%. The fully fortified 16% CP diet in Trial 4 produced gain:feed ratios but not gain values similar to those achieved with the 24% CP diet. In chicks fed the unsupplemented 16% CP diet, body fat deposition was increased markedly, relative to that observed with either the 24% CP or the AA-supplemented 16% CP diet. The data of these trials reveal that Met, Arg, Lys, Thr, and Val are the critical limiting AA in a low-protein corn-soybean meal diet fed to broiler chicks.

Limiting Amino Acids in Low-Protein Corn-Soybean Meal Diets for Growing-Finishing Swine

Limiting Amino Acids in Low-Protein Corn-Soybean Meal Diets for Growing-Finishing Swine

Response to Methionine Supplementation of Leghorn Hens Fed Low-Protein Corn-Soybean Meal Diets

When 0.05% or 0.10% methionine was added to diets containing 12% protein and daily feed consumption of control hens was near 90 g., feed intake was depressed, resulting in lowered egg production, egg weight and body weight. When 16% protein diets were methionine-supplemented and daily feed consumption was 90 g., egg production and egg weight increased.Because the reduced performance could not be explained by expressing the amino acid concentrations as a percentage of the diet, percentage of the protein or percentage per kcal. of M.E., an experiment was conducted to study the additions of 0.05% and 0.10% methionine to diets of different nutrient density, but containing a constant calorie:protein ratio, thereby studying the feasibility of expressing methionine concentrations as a (percentage of methionine/kcal. of M.E./kg. of diet)/percentage of protein. Methionine additions to a diet containing 13.5% protein and 2600 kcal. M.E./kg. resulted in reduced production as methionine concentration was increased from 0.0056 to 0.0071 to 0.0085. Methionine additions to a diet containing 15.5% protein and 3000 kcal. M.E./kg. resulted in methionine concentrations of 0.0050, 0.0060 and 0.0071 and a marked linear improvement in performance. The expression of the methionine concentrations in this manner provides a useful means of predicting the hen’s response to methionine supplementation under different conditions if the resulting concentrations can be compared with a reference diet known to respond to methionine additions.

Efficacy of Supplemental Lysine, Methionine and Rolled Oats for Weanling Pigs Fed a Low-Protein Corn-Soybean Meal Diet

Efficacy of Supplemental Lysine, Methionine and Rolled Oats for Weanling Pigs Fed a Low-Protein Corn-Soybean Meal Diet