SEARCH · PubMed Health

Results for “feed efficiency”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources

PubMed2002

Dietary vitamin C and vitamin E interact to influence growth and tissue composition of juvenile hybrid striped bass (Morone chrysops (female) x M. saxatilis (male)) but have limited effects on immune responses.

Juvenile hybrid striped bass (initially 12.0 g) were fed diets containing deficient, adequate or excessive amounts of vitamin C and/or vitamin E in a factorial arrangement to investigate potential nutritional interaction and effects on immune responses. Nine semipurified diets were supplemented with 0, 25 or 2500 mg vitamin C/kg and 0, 30 or 300 mg vitamin E/kg and fed to fish in triplicate aquaria for 10 wk. Weight gain, feed efficiency, mortality and tissue vitamin levels were significantly (P < or = 0.05) affected by dietary vitamin levels. In addition, a significant interaction between vitamin C and vitamin E was observed. At inclusion levels of 25 and 2500 mg/kg, dietary vitamin C improved feed efficiency and protected fish fed vitamin E-deficient diets from growth depression and mortality. At inclusion levels of 30 and 300 mg/kg, vitamin E prevented mortality in fish fed vitamin C-deficient diets; however, 300 mg vitamin E/kg was necessary to prevent growth depression in vitamin C-deficient fish but was unable to improve feed efficiency. Lysozyme, bacterial killing ability, as well as plasma protein and total immunoglobulin levels of fish were not affected by dietary vitamin levels, whereas respiratory burst activity increased with vitamin E supplementation. Thus, interactions between vitamin C and vitamin E were observed in hybrid striped bass. These interactions may be due to the ability of vitamin C to regenerate vitamin E to its functional form but also suggest an ability of vitamin E to spare vitamin C.

Analysis of Variance↗

PubMed1997

The response of broiler chickens and turkey poults to dietary energy supplied either by fat or carbohydrates.

The efficacy of fat and carbohydrates as energy sources was compared in 1- to 4- and 4- to 7-wk-old broiler chickens and in 16- to 19-wk-old turkeys. An increase in dietary energy by carbohydrate was made by a graded replacement of wheat bran by wheat. Energy was increased by fat through a graded replacement of soybean hulls with refined soybean oil. In the experiments with broiler chickens, the feed efficiency responses to added energy were observed within the entire range of dietary energy tested, with no significant differences between the responses to carbohydrate and fat as energy supplements. The growth response to energy from either source appeared to be characterized by diminishing returns in the chicken. In the 16- to 19-wk-old turkeys, the growth and feed efficiency responses were linear within the range from 2,650 to 3,250 kcal/kg. In chickens and in turkeys, the growth and feed efficiency responses to energy supplied by fat were indistinguishable from those of carbohydrates. In chickens, the fractions of abdominal fat and pectoral muscle were not affected significantly by the energy density and source.

Adipose Tissue↗

PubMed1989

Compensatory weight gain in steers recovered from oak bud toxicosis.

Cattle that had recovered from clinical oak bud toxicosis (as assessed by normal BUN and serum creatinine values and good appetite) performed better than did clinically normal herdmates when weight gain and feed efficiency were compared. Both groups had a rate of weight gain (oak bud-exposed cattle, 1.76 kg/steer/d; control cattle, 1.57 kg/steer/d) that exceeded the feedlot mean value (approximately 1.4 kg/d) for cattle (of similar starting weight and diet) that had zeranol implants, and the difference was significant (P less than 0.005) for both groups. The difference in weight gain performance of oak bud-exposed cattle, compared with control cattle, was not highly significant; however, the improved feed efficiency was significantly (P less than 0.05) better than that in controls (2.57 kg of feed/kg of weight gain vs 3 kg of feed/kg of weight gain). On the basis of accepted criteria (increased rate of weight gain and efficiency of feed conversion), the group of oak bud-exposed cattle of this study had compensatory weight gain. Thus, cattle with good evidence of clinical recovery from oak bud toxicosis can be expected to perform in the feedlot at least as well as cattle not exposed to oak bud toxicosis, and may have compensatory weight gain.

Animal Feed↗

PubMed2007

Galanin type 1 receptor knockout mice show altered responses to high-fat diet and glucose challenge.

Galanin, a brain and pancreatic peptide with three receptor subtypes (GALR1, GALR2, and GALR3), is hypothesized to participate in energy homeostasis and glucoregulation. Hypothalamic galanin expression is induced by dietary fat, and intra-hypothalamic galanin administration has orexigenic/anabolic properties. Systemic galanin infusion alters glucoregulation in non-human species, partly through direct actions on pancreatic islets. However, the physiologic significance of endogenous galanin-GALR signaling is unclear. The present studies tested the hypotheses that GALR1 deficiency alters food intake and feed efficiency following switches to high-fat diet and that GALR1 deficiency alters whole-body glucose homeostasis. Adult, male GALR1 knockout (-/-), heterozygote (+/-), and C57BL/6J control (+/+) mice were studied. GALR1 deficiency impaired adaptation to a 3-day high-fat diet challenge, leading to increased food intake, feed efficiency and weight gain. However, during the following 2 weeks, GALR1 knockout mice decreased intake, consuming less daily energy than while maintained on low-fat diet and also than heterozygote littermates. Chow-maintained GALR1 knockout mice showed relative hyperglycemia in fed and d-glucose (i.p. 1.5 g/kg)-challenged states. GALR1 knockout mice showed normal food intake, feed efficiency and weight accrual on low-fat diets, normal fasted glucose levels, and normal glucose sensitivity to porcine insulin (i.p. 1 IU/kg) in vivo. The results support the hypotheses that galanin-GALR1 systems help adapt food intake and metabolism to changes in dietary fat and modulate glucose disposition in mice.

Adaptation, Physiological↗

PubMed1987

Replacement of skimmed milk with hydrolyzed fish protein and Nixtamal in milk substitutes for dairy calves.

Two experiments were conducted with 3- to 5-d-old Holstein male calves. In Experiment 1, 15 calves were assigned to three dietary treatments. The control diet was based on sodium caseinate, lard, and cerelose. In the other diets, either 50% or all carbohydrates were replaced by lime-treated corn flour (Nixtamal). In Experiment 2, 35 calves were assigned to dietary treatments in which 0, 50, or 67% low heat skimmed milk protein was replaced by hydrolyzed fish protein; for the replacement diets, Nixtamal was incorporated at 25 or 35% of the dry matter. Control diet protein was entirely from skimmed milk. Milk substitutes provided the only feed during the 8-wk experiment. In Experiment 1, body weight gain and feed efficiency declined when Nixtamal completely replaced skimmed milk but remained unchanged at 50% substitution. Substitution of Nixtamal for skimmed milk powder decreased nitrogen and carbohydrate digestibility; but digestibility improved with age. In Experiment 2, replacing up to 67% of skimmed milk protein with partially hydrolyzed fish protein concentrate had no effect on body weight gain but decreased feed efficiency linearly at 8 wk and reduced dry matter, nitrogen, and fat digestibility. Nixtamal can replace up to 50% of skimmed milk carbohydrates without detrimental effect on growth rate, feed efficiency, and diarrhea, but digestibility might be reduced. Concurrent replacement of up to 67% of skimmed milk protein with partially hydrolysed fish protein concentrate would be feasible for newborn calves gaining 450 g/d, despite lower nitrogen digestibility.

Animal Nutritional Physiological Phenomena↗

PubMed1995

The nutritional value of high-oil corn for broiler chicks.

A variety of corn (Natan) with high fat and protein contents (6.7 and 9.8%, respectively) was developed at Newe Ya'ar, Israel. The nutritive value of this corn for broiler chicks from 7 to 28 d of age was evaluated in two experiments. In the first experiment, Natan and a local conventional corn variety (LCC-2.9% fat and 7.2% protein) were incorporated in a relatively low-protein diet designated for the determination of AMEn by the substitution method. The AMEn content of Natan was found to be 3,658 kcal/kg, whereas that of LCC was 3,437 kcal/kg. There were no differences in feed intake or weight gain between chicks fed the two corn varieties, but feed efficiency of those fed the diet containing Natan was improved (P < .05). In the second experiment, the effects on the performance of chicks of diets adequate in protein and containing either imported conventional corn (ICC), or Natan, or ICC-enriched with corn oil and soybean meal (to equalize its fat and protein content to that of the diet containing Natan), were compared. There were no differences in feed intake or weight gain among chicks fed the three diets and in feed efficiency among chicks fed the diet containing Natan and those fed the other two diets, whereas, the enrichment of the ICC-containing diet significantly improved feed efficiency. It was concluded, therefore, that in spite of the high nutritional value of the high-oil corn, its effect on improving the performance of chicks, when replacing a conventional corn in a well-balanced diet, was not pronounced.

Animal Feed↗

PubMed1981

Effects of dietary protein and energy on growth, feed conversion efficiency and body composition of Tilapia aurea.

The optimum dietary protein to energy (P:E) ratio for rapid and efficient gain of juvenile Tilapia aurea was shown to fall with increasing size of fish. The optimum concentration of protein and energy also fell with growth. A diet providing roughly 56% protein at 4,600 kcal/kg digestible energy (gross energy adjusted for indigestible fiber) with a P:E ratio of 123 mg potential/kcal produced highest gains of fry (2.5 g). Larger fish (7.5 g) grew most rapidly when fed a 34% protein, 3,200 kcal/kg diet with a P:E ratio of 108. Apparent feed conversion (grams of feed offered/grams of fish weight gain) was superior on diets having lower P:E ratios and was best on the 34% protein, 3,200 kcal/kg diet. Linear regression analysis indicated highly significant differences in average fish weight, condition [10(5) x weight (g)/total length (mm)3], and feed conversion efficiency attributable to changes in either protein or energy concentration. Significant interaction between protein and energy was also demonstrated. Condition and level of carcass fat were high on all diets which produced good growth rates and were inversely related to P:E ratio. Moisture and ash were inversely related to carcass fat. No trend was established for carcass protein.

Animals↗

PubMed1990

Effect of intermittent lighting on the reproductive performance of first-year and recycled turkey hens.

In each of two trials, a 2-by-2 factorial arrangement of treatments was utilized to evaluate the reproductive performance of first-year and recycled turkey hens to intermittent lighting (IL) through an egg-laying period of 20 wk. The IL treatment provided 4 h of light per day given as 2 h light:12 h dark:2 h light:8 h dark (2L:12D:2L:8D). This treatment group was compared to controls maintained on 16L:8D. Data were collected for BW, feed intake, feed efficiency, time to first egg, eggs per hen fertility, hatchability, egg weight, and poult weight. Consistent age effects included greater BW, egg weight, and poult weight from recycled hens compared to first-year hens as well as a delay in the onset of laying and a reduction in egg production by six eggs per hen in the recycled hens. Feed intake and feed efficiency were similar in both age groups, Intermittent lighting delayed the onset of laying but increased the rate of lay by eight eggs per hen. Late-season fertility, feed efficiency, and egg weight were significantly increased by the IL treatment. The conclusion was that, for turkey hens, intermittent lighting can effectively improve reproductive performance.

Age Factors↗

PubMed2004

Intestinal villus histological alterations in piglets fed dietary charcoal powder including wood vinegar compound liquid.

To investigate the effects of dietary charcoal powder including wood vinegar compound liquid (CWVC, 4 : 1) on intestinal villus histology, piglets were fed 0, 1, 3 and 5% dietary CWVC diets for 30 days. Feed intake and body weight gain were measured during the experimental period. At the end of the experiments, intestinal villus height, epithelial cell area and cell mitosis were examined using light microscopy (LM), and the duodenal villus tip surface was observed using scanning electron microscopy (SEM). Feed efficiency tended to be improved in the CWVC group. The 3% CWVC group showed the highest value, followed by 1% CWVC group of most LM parameters in most intestinal parts, but the 5% CWVC group showed the almost similar value compared with the control. In addition, on the duodenal villus tip surface, the 3% CWVC group showed a clearer cell outline, larger cells and cells protuberated further into the lumen than those of the 1% CWVC group. However, the 5% CWVC group showed faint SEM features than the 1% CWVC group. The present trend of improved feed efficiency after feedings of dietary CWVC demonstrates that the CWVC could be incorporated into piglet diets up to 3% level, and that the CWVC might activate intestinal functions both at villus and cellular levels.

Acetic Acid↗

PubMed1997

Phenotypic characterization of rambouillet sheep expressing the callipyge gene: I. Inheritance of the condition and production characteristics.

The objectives of this study were to determine the model of inheritance of the callipyge gene and to evaluate the growth, ADFI, feed efficiency, reproductive performance, and wool growth of sheep that are heterozygous for the callipyge gene. Ewes (n = 236) with a normal muscle phenotype and genotype were mated to three heterozygous rams that expressed the callipyge gene. Lambs (n = 311) were subjectively classified at weaning (90 to 120d) according to muscle phenotype by a panel of three evaluators working independently. The callipyge muscle phenotype was expressed in 150 lambs, whereas 161 lambs expressed a normal muscle phenotype. The percentage of lambs expressing the callipyge muscle phenotype (48.2%) did not differ (P > .1) from the expected 50%. Growth rate was similar for lambs of both phenotypes regardless of sex. Feed efficiency was superior (P < .05) for both male and female lambs with the callipyge muscle phenotype. Average daily feed intake was lower for male (P < .02) and female (P < .004) lambs with the callipyge muscle phenotype. Grease fleece weight and staple length at 12 mo were superior (P < .03) for ewes with a normal muscle phenotype. These results indicate that the callipyge gene in sheep is dominant when inherited from the paternal parent and lambs expressing the callipyge gene have increased feed efficiency and reduced ADFL.

Animals↗

PubMed1994

The effect of beak trimming on two strains of commercial tom turkeys. 1. Performance traits.

Two commercial strains (Strains A and B) of tom turkeys were either beak trimmed or left with intact beaks. These strains responded similarly to beak trimming for performance traits, with the exception of a higher incidence of beak-inflicted injuries among Strain B toms with intact beaks. Turkeys with trimmed beaks had higher body weights at 8, 12, and 16 wk. Feed efficiency was better in beak-trimmed birds from 4 to 8 wk, 12 to 16 wk, and 0 to 18 wk. Beak treatment did not effect mortality. Leg abnormalities caused the majority of culling or resulted in death or culling from beak-inflicted injuries. Beak trimming seems to be a beneficial practice in tom turkeys because feed efficiency of beak-trimmed toms was improved and injuries were reduced in a strain that tended to exhibit a high degree of beak-inflicted injuries. The results suggest that the need for beak trimming tom turkeys may be reduced when feed efficiency of toms with intact beaks is improved.

Animals↗

PubMed1995

Growth in iron-deficient rats.

Poor growth in iron deficiency is commonly observed in animal studies. Previous studies from our laboratory showed that iron-deficient rats are metabolically inefficient and have less body fat than controls and proposed that iron deficiency was related to increased metabolic rates and heat loss. To examine these points more completely, we examined growth and metabolic rate of iron-deficient rats at two environmental temperatures, 25 degrees C and 32 degrees C, and feed efficiency in separate groups of rats during a period of rapid growth. Iron deficiency (hemoglobin [Hb] approximately 60 g/liter) was associated with a systematic elevation of metabolic rate over the 24-hr day with animals at 25 degrees C. This did not occur in animals living in thermoneutrality. Iron deficiency affected growth of animals at 25 degrees C but not at 32 degrees C. Feed efficiency (kcal retained/kcal absorbed) was 25 +/- 4.2 and 31 +/- 4.9 kcal (P < 0.0001), respectively, in iron deficient rats and animals were not anorexic. Use of food-restricted animals allowed the direct calculation that iron deficiency was associated with a 10%-15% increase requirement for growth. We conclude that iron deficiency anemia is associated with a poor feed efficiency and that it is attenuated when nonshivering thermogenesis is minimized by a thermoneutral environment.

Anemia, Iron-Deficiency↗

PubMed1975

Replacing dietary methionine and cystine in chick diets with sulfate or other sulfur compounds.

A purified diet deficient in the sulfur amino acids and sulfate was fed to chicks in tests designed to compare the effectiveness of several sulfur compounds in sparing the sulfur amino acids. The addition of a mixture of methionine and cystine to this diet increased growth rate and feed efficiency more than any of the other additions. Sulfate improved performance as much as any inorganic sulfur source tested. Taurine, sulfite, thiosulfate, and sulfur also had value. When graded levels of sulfate were added to diets with sulfur amino acid levels about 0.2 and 0.3% below the level required for optimum performance, the weight gain and feed efficiency response curves were curvilinear. Most of the response to sulfate was produced with a level of 200 p.p.m., but 500 to 660 p.p.m. was needed to produce the maximum sparing effect. The sulfur amino acid requirement was found to be about 0.075% less with 0.1% sulfate in the diet than without it when growth rate was the criterion. When feed efficiency was the criterion, the requirement was reduced about 0.05% by sulfate.

Animals↗

PubMed2006

Increasing the physically effective fiber content of dairy cow diets may lower efficiency of feed use.

Barley silages varying in theoretical chop length were used to evaluate the effects of physically effective (pe) neutral detergent fiber (NDF) content of dairy cow diets on nutrient intakes, site and extent of digestion, microbial protein synthesis, and milk production. The experiment was designed as a replicated 3 x 3 Latin square using 6 lactating dairy cows with ruminal and duodenal cannulas. During each of 3 periods, cows were offered 1 of 3 diets (low, medium, and high peNDF) obtained using barley silage that varied in particle length: fine (theoretical chop length of 4.8 mm), medium (equal proportions of long and fine silages), and long (theoretical chop length of 9.5 mm). The peNDF contents were determined by multiplying the proportion (dry matter basis) of feed retained on the 2 screens (8 and 19 mm) of the Penn State Particle Separator by the NDF content of the diet, and were 10.5, 11.8, and 13.8% for the low, medium, and high diets, respectively. Increased forage particle length linearly increased intake of peNDF but intakes of dry matter, organic matter, starch, and N were highest for cows fed the medium peNDF diet. Digestibilities of organic matter, NDF, and acid detergent fiber in the total tract were linearly decreased with increasing dietary peNDF, although total digestibility of starch and N was not affected by the treatments. Nevertheless, decreased digestibility due to increased dietary peNDF did not reduce milk production or milk composition because the cows were in mid to late lactation. Ruminal microbial protein synthesis and microbial efficiency were numerically higher with the low peNDF than with the medium or high peNDF diets. These results indicate that increasing the peNDF content of a diet containing barley silage decreases fiber digestibility in the total tract and lowers microbial efficiency. Therefore, the benefits of increasing dietary particle size, expressed as peNDF, on reducing the risk of ruminal acidosis should be weighed against potentially negative effects on efficiency of feed use.

Animal Nutritional Physiological Phenomena↗

PubMed2004

Effect of alfalfa meal in diets of laying quails on performance, egg quality and some serum parameters.

This study was conducted to investigate the effects of increasing levels of alfalfa meal in the diet of laying quails on egg production, feed consumption, feed efficiency, egg quality, egg yolk cholesterol and selected serum parameters. In this study, 192, 10-week old quails (Coturnix coturnix japonica) were evenly distributed to four groups with four replicates of 12 quails each. The control group was fed a basal diet containing 0% alfalfa meal and the remaining groups received 3, 6 or 9% alfalfa meal for 12 weeks. Live weight, feed consumption, and egg production were recorded and feed efficiency were calculated. Eggs were examined for interior and exterior quality and egg yolk cholesterol content. At the end of the experiment, blood samples were collected and sera were analysed for serum Ca, inorganic P (P(i)), Mg, triglycerides and total cholesterol. Any level of alfalfa meal had no effect on live weight, egg production, feed consumption, feed efficiency, egg weight, and egg yolk index. Six percent and 9% alfalfa meal increased specific gravity of whole egg and eggshell thickness as well as serum P(i) levels. Nine percent alfalfa meal reduced serum triglycerides, total cholesterol levels and egg yolk cholesterol content. The results of this experiment indicated that addition of 9% alfalfa meal into the laying quail diet may improve eggshell quality and reduced serum triglycerides and serum and egg yolk cholesterol without any adverse effect on performance.

Animal Feed↗

PubMed1984

A repartitioning agent to improve performance and carcass composition of broilers.

Clenbuterol [benzyl alcohol, 4-amino-alpha-(t-butylamino)methyl-3,5-dichloro] was tested in the finisher ration of broilers in three series of experiments for its effects on performance and carcass characteristics. In Experiment 1, administration of clenbuterol at feed levels of .25, .5, 1, 2, and 4 ppm from 28 to 49 days of age resulted in significant sex combined weight gain improvements at all levels except 4 ppm and significant feed efficiency improvements at all levels tested. Uneviscerated body composition analysis indicated that clenbuterol treatment significantly increased body protein and water content and decreased body fat in female birds. In males, body fat was significantly reduced by 1, 2, and 4 ppm clenbuterol. From these results the 1 ppm level was selected for further testing. In Experiments 2 and 3, clenbuterol fed from 28 to 49 days of age significantly improved sex combined weight gain and feed efficiency and both male and female 49-day weights. Carcass yield was significantly increased in males and females by 1.11 and 1.91 percentage points, respectively. Abdominal fat was significantly reduced by clenbuterol feeding only in females. Carcass analysis indicated that clenbuterol-fed birds had a significantly lower carcass fat content. In Experiments 4 to 7, clenbuterol was administered at 1 ppm in the finishing feed but was withdrawn 3 to 5 days prior to terminal performance and carcass evaluations. Clenbuterol significantly improved sex combined weight gain and feed efficiency, and 49-day weights for both sexes. Carcass yield was significantly increased in males and females by .54 and .98 percentage points, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1984

Behavior and growth parameters of large white turkeys as affected by floor space and beak trimming. 1. Males.

The effects of floor space and beak trimming on behavior and growth of Large White male turkeys were investigated Floor space allowances were 6.5, 9.3, and 12.1 dm2/bird at 0 to 8 weeks; 11.7, 16.7, and 21.8 dm3/bird at 8 to 12 weeks; and 28, 35, and 42 dm3/bird at 12 to 20 weeks. Floor space was adjusted by changing the pen size while maintaining a constant number of birds per pen. Body weight, feed intake, feed efficiency, feather score, live market quality, and mortality were measured. In addition, agonistic behavior including "threat avoids", "peck avoids", "threat chases", "peck chases" and "fights", and nonagonistic behavior including feather "pecks" and "pecks and pulls" were determined at 12 and 20 weeks of age. Floor space had no significant effect on any parameter measured through 8 weeks. At 12 weeks, feed efficiency and body weight were significantly decreased with decreasing floor space. By 20 weeks, the body weight of the birds grown at the intermediate floor space allowance from 8 to 12 weeks was no longer significantly different from those grown at the highest floor space allowance; however, the birds grown at the highest density from 8 to 12 weeks remained significantly lighter at 20 weeks. Compensatory growth, if present, appeared limited. Beak trimming had no significant effect on body weight or feed efficiency. Food intake was significantly greater in the beak trimmed birds from 12 to 18, but there was no significant difference from 12 to 20 weeks. From 12 to 20 weeks, mortality was significantly less in beak-trimmed birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggression↗

PubMed1975

Effects of substitution of methionine, leucine, phenylalanine, or valine by their alpha-hydroxy analogs in the diet of rats.

Weanling male rats were fed diets containing essential amino acids as the sole source of nitrogen at a level of either 6 or 15% by weight of the diet. When L-valine was replaced isonitrogenously by calcium L-alpha-hydroxyisovalerate in the 15% amino acid diet, growth ceased and urea excretion increased; urea clearance was unaffected. When L-leucine was replaced isonitrogenously by calcium L-alpha-hydroxyisocaproate in this diet, growth and feed efficiency fell approximately 60% and urea excretion rose, but urea clearance doubled. L-Phenylalanine was replaced both isonitrogenously and without supplemental glutamate by calcium L-phenyllactate in both the 6 and 15% amino acid diets and was also added in twice equimolar quantities to the 6% amino acid diet. When the 15% amino acid diet was fed, growth was severly reduced, but when the 6% diet was fed, the double dose of phenyllactate reduced growth and feed efficiency only 25%. Urea clearance was not consistently altered. When D,L-methionine was replaced by calcium K,L-alpha-hydroxy-gamma-thiobutyrate in the 15% amino acid diet, growth and feed efficiency improved whether or not glutamate was added to make diets isonitrogenous, and also whether or not 0.1% neomycin was included. Urea clearance did not differ among these groups but was significantly higher in rats receiving the hydroxy analog or D,L-methionine than that in controls receiving L-methionine. Thus, the ability of these hydroxy analogs to replace the corresponding amino acids in the diet of rats varies from complete (methionine) to partial (leucine and phenylalanine) or virtually nonexistent (valine).

Animal Nutritional Physiological Phenomena↗