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Biomedical subjects

G M Pesti

Publications and source records attributed to G M Pesti.

At least 19 recordsLinked to original sources
PubMed1999

Studies on semduramicin and nutritional responses. 1. Level and source of protein.

An experiment was conducted to determine whether feeding semduramicin at recommended levels (25 mg/kg) would affect the broiler chicken's response to dietary protein; and to determine whether protein source (all vegetable, corn and soybean meal, vs 12% high animal protein ingredients) would affect the response to semduramicin. Semduramicin was fed to half of 1,584 male Ross x Ross broilers in floor pens during the growing phase (18 to 35 d). Three protein fortification levels were also fed with protein and amino acid minimum restrictions at 80, 100, and 120% of NRC (1994) recommendations. At 35 d, semduramicin was found to cause a slight growth depression in body weight gain only when low protein levels were fed (P = 0.051). After a 7-d withdrawal period, compensatory gains occurred (P = 0.006) such that there was no interaction effect of semduramicin by protein level for 42-d body weight (P = 0.75). Birds fed the diets containing high animal protein were slightly heavier than those fed control diets containing all-vegetable protein (2.40+/-0.02 vs 2.36+/-0.01 kg/bird; P = 0.059). Semduramicin feeding did not affect feed consumption (2.43+/-0.03 vs 2.40+/-0.02 kg per bird during the growing period when it was fed) so that overall feed conversion ratios were identical to two decimal places (1.90+/-0.02 vs 1.90+0.02). Neither did semduramicin affect feathering score or weight of the No. 8 primary feather, except that feather weight tended to be improved by semduramicin feeding with the diets containing ingredients high in animal protein (P = 0.067).

Animal Nutritional Physiological Phenomena↗
PubMed1999

Studies on semduramicin and nutritional responses: 2. methionine levels.

Three experiments were conducted to determine whether feeding semduramicin at recommended levels would affect the broiler chicken's response to dietary methionine. In Experiment 1, three levels of methionine (0, 0.15, 0.30%) were fed to chicks in battery brooders. In Experiment 2, two levels of protein (18 and 22%) and three levels of methionine (0, 0.15, 0.30%) were fed to chicks in floor pens from 18 to 44 d. In Experiment 3, two methionine supplements were fed during each of the starter (0 and 0.21%, 0 to 18 d) and grower (0 and 0.10%, 18 to 35 d) periods to chicks in floor pens. In all experiments, male commercial broiler chicks were used, and all diets were fed with and without 25 mg/kg diet of semduramicin. The basal diets were based on corn, soybean meal, and poultry oil. In Experiment 1, there was a growth and feed conversion ratio response to methionine supplements, but there was no effect of semduramicin on growth nor any semduramicin by methionine supplement interaction. In Experiment 2, at 44 d, protein and methionine levels both influenced feed conversion ratios, but semduramicin did not. Feeding 22 vs 18% protein increased carcass and breast muscle yields and decreased abdominal fat pad weights. The results of Experiments 2 and 3 were very similar. Overall, the effects of semduramicin on growth and processing parameters were small and not significant, but considerable benefits in performance and carcass parameters could be realized by feeding the higher levels of protein or methionine.

Animals↗
PubMed1998

Studies on the effect of feeding cupric sulfate pentahydrate to laying hens on egg cholesterol content.

Two experiments were conducted to test the hypothesis that pharmacological levels of dietary Cu could reduce egg cholesterol content. White Leghorn hens 30 to 39 wk of age were fed corn and soybean meal diets with 0, 125, or 250 mg supplemental Cu/kg diet from cupric sulfate pentahydrate (basal diet = 6.74 mg Cu/kg). Body weight, feed consumption, egg weights, egg specific gravity, and Haugh Units were not consistently affected during the 8-wk feeding trials. Egg production was significantly increased (P < 0.05) in the second 4-wk period by supplemental Cu in both experiments. Egg yolk cholesterol concentrations were decreased by feeding 125 mg Cu/kg diet (11.7 vs 8.6 mg/g, average of two experiments); feeding 250 mg Cu/kg resulted in further declines in egg cholesterol but the differences were not significant (7.9 mg/g). Changes in plasma cholesterol concentrations were similar to those of yolk cholesterol. Small but significant amounts of Cu accumulated in the yolks and shells of eggs from Cu-supplemented hens; however, most of the Cu fed was found in the excreta.

Animal Feed↗
PubMed1998

Further studies on the influence of genotype and dietary protein on the performance of broilers.

An experiment was conducted to quantify genetic differences in response to dietary protein level of male vs female broilers. Broilers (1 d old) from a "high-yield" strain cross (Ross x Ross 208) and a "fast-growing" strain cross (Peterson x Arbor Acres) were placed on fresh pine shavings in floor pens. From Day 0 to 18, all birds were fed a 23% CP starter diet. During Days 18 to 53 male birds were fed either a 16, 18, 20, 22, 24, or 26% CP diet (3,200 kcal ME/kg) and female birds were fed the 16, 20, or 24% CP diet. Significant differences (P < 0.05) were noted in the performance of the different strains. Ross x Ross 208 male birds had a higher body weight (3.37 vs 3.16 kg), higher feed intake (7.08 vs 6.78 kg), higher breast yield (31.76 vs 29.25%), higher carcass yield (73.90 vs 71.85%), and a lower adjusted feed conversion ratio (FCR; 2.10 vs 2.16 g:g) than Peterson x Arbor Acres males at 53 d of age. As compared to Peterson x Arbor Acres females, Ross x Ross 208 female broilers also had a higher body weight (2.68 vs 2.55 kg), higher breast meat yield (33.61 vs 30.80%), higher carcass yield (75.31 vs 73.91%), and lower adjusted FCR (1.97 vs 2.04 g:g). Qualitative differences in the response of these strains were confirmed and better qualitative data is presented that can be used to predict the important output parameters from the import inputs in broiler production.

Aging↗
PubMed1998

Influence of broiler strain cross and dietary protein on the performance of broilers.

The purpose of this experiment was to quantify the responses of two broiler strain crosses to different dietary protein levels on performance and carcass yields. Day-old broiler chicks from a high-yield strain cross (Ross x Ross 208) and a fast-growing strain cross (Peterson x Arbor Acres) were placed in floor pens on fresh pine shavings. All birds were fed a 23% CP starter for the first 18 d. During Days 18 to 53, birds were fed either 16, 20, or 24% CP diets (3,200 kcal ME/kg). At 53 d of age, significant differences (P < 0.05) were noted in the performance of the strains. Overall, Ross x Ross birds had higher body weights (3.29 vs 3.10 kg), higher feed intakes (6.40 vs 6.11 kg), and higher carcass yields (72.51 vs 71.17%), although the differences were dependent on dietary protein levels. Strain cross had no significant effect on feed conversion (1.95 g feed: g gain vs 1.97 g:g). Results indicated that both strain cross and protein level had effects on body weight and feed intake, and there were significant strain cross by protein level interactions for body weight and carcass weight. Increasing dietary protein level increased body weights more for the Ross x Ross 208 than for the Peterson x Arbor Acres broilers. Feed conversion was indirectly proportional to dietary protein level, but was not affected by strain cross. Percentage carcass yield was greatly affected by strain (P < 0.0001), but protein level had no significant effect (P = 0.68). The significant interactions indicate that different strain crosses should have different feeding programs to maximize profitability.

Age Factors↗
PubMed1998

Studies on the feeding of cupric sulfate pentahydrate, cupric citrate, and copper oxychloride to broiler chickens.

Male commercial broiler strain chickens were fed either a control diet (based on corn and soybean meal) or the control diet supplemented with cupric sulfate pentahydrate, copper oxychloride, or cupric citrate in two experiments conducted in floor pens. In Experiment 1, feeding copper at 125 mg/kg diet for 42 d significantly increased broiler growth; and the response from cupric citrate was significantly better than either cupric sulfate or copper oxychloride. In Experiment 2, the inclusion of copper from cupric citrate was reduced to 63 mg/kg and the length of the experiment was increased to 56 d. Cupric sulfate pentahydrate and copper oxychloride treatments increased weight gain by 4.9% and cupric citrate increased weight gain by 9.1%. The feed conversion ratios (grams of feed:grams of gain of live birds) in the birds fed copper were not significantly different from those fed the basal diet (P > 0.05) unless corrections were made for the weights of the dead birds; the adjusted feed conversion ratios (grams of feed:grams of gain of live birds + grams of gain of mortalities) for the copper-treated birds in Experiments 1 and 2 were 5.2 and 7.6% lower, respectively, than the ratios of birds fed the basal diets. Plasma copper levels increased in supplemented chicks by 35% in Experiment 1 and 24% in Experiment 2. Liver copper levels in both experiments were increased by 26% with copper supplementation. Mortality was not affected by dietary treatment in either experiment (P > 0.05).

Animal Feed↗
PubMed1997

Estimation of the composition of broiler carcasses from their specific gravity.

An experiment was conducted to quantify the relationships between broiler carcass specific gravity and chemical composition (percentage moisture, percentage lipid, percentage protein). Carcasses of widely varying compositions were produced by feeding several dietary protein and energy combinations (52 to 64% moisture, 0.6 to 2.5% ash, 1.6 to 11.7% lipid, and 4.9 to 8.0% nitrogen). Very strong relationships were found between percentage moisture and percentage lipid (r = -0.969) and percentage moisture and percentage N (r = 0.968). Strong relationships were found between specific gravity and percentage lipid (r = -0.872) and specific gravity and percentage N (r = 0.857). Specific gravity is recommended as a means to estimate carcass fat in broiler chickens.

Animals↗
PubMed1997

Modulation of cholesterol levels in broiler meat by dietary garlic and copper.

Male Ross x Ross 208 chickens were fed from hatching to 21 d of age either a control diet (based on corn and soybean meal) or the control diet supplemented with 0, 1.5, 3.0, and 4.5% of a commercial garlic powder in Experiments 1 and 2. Once the dose-response relationship was established, 3% garlic powder or 63 or 180 mg/kg copper as cupric citrate or cupric sulfate pentahydrate were supplemented to the diet (Experiments 3, 4, 5, and 6). In the first two experiments, reductions of plasma cholesterol (P = 0.006) and triacylglycerols (P = 0.013) and liver (P = 0.012) and breast muscle (P = 0.165) cholesterol were observed in garlic-supplemented birds. Feeding either garlic powder or copper (63 and 180 mg/kg) resulted in reduced levels of plasma cholesterol, liver cholesterol, blood reduced glutathione, and breast and thigh muscle cholesterol. Differences were significant at P < 0.05 in at least one experiment. 3-Hydroxy-3-methylglutaryl reductase activity was decreased due to dietary garlic (P = 0.0369), but not by pharmacological levels of dietary copper (P = 0.982). The activity of fatty acid synthetase was decreased in birds fed copper (P = 0.035). Both garlic and copper supplements decreased cholesterol 7 alpha-hydroxylase activity (P = 0.024 and P = 0.022, respectively). The results of these trials confirm the findings that garlic and copper alter lipid and cholesterol metabolism. However, they do not work by the same mechanism. Feeding dietary garlic or copper for 21 d reduced cholesterol levels of broiler meat without altering growth of the chickens or feed efficiency.

Animals↗
PubMed1997

A new method for determining the availability of choline in soybean meal.

Studies were conducted to evaluate the availability of choline in soybean meal, using a new approach: The basal diet contained soybean meal with a lowered choline content (partially extracted with methanol). Choline was added to the basal diet 1) by substituting intact soybean meal for the methanol washed soybean meal; or 2) from crystalline choline Cl. Four experiments were conducted with day-old male broilers housed in battery brooders and fed the experimental diets from 4 to 18 d posthatching. The basal diet contained corn, soybean meal, and isolated soy protein in Experiments 1 to 3, and also glucose in Experiment 4. In Experiment 1, chicks fed the basal diet (1,140 mg/kg choline, 0.61% sulfur amino acids) had a growth response to 1,000 mg/kg choline or 0.10% methionine (P < 0.05), but not to 0.10% cysteine (P > 0.05) supplementation. Supplementation of choline (0, 50, 100, 200, 400, 800, and 1,200 mg/kg) to the basal diet (1,230 mg/kg choline) in Experiment 2 resulted in a linear increase in growth up to 122 +/- 22 mg/kg supplemental choline (1,352 +/- 22 mg/kg total choline), reaching a plateau after that. In the slope ratio assays to determine choline availability, the basal diets in Experiments 3 (1,098 mg/kg choline) and 4 (920 mg/kg choline) were supplemented with either 50 or 100 mg/ kg choline (from choline Cl) or had approximately 50 or 100 mg/kg choline added with intact soybean meal (at the expense of washed soybean meal). There were significant linear responses of weight gain vs choline intake from either source (P < 0.001). The availability of choline in soybean meal was calculated to be 97 and 105% in Experiments 3 and 4, respectively. These results indicate that choline availability in soybean meal is close to 100%.

Animals↗
PubMed1996

Effects of the naked neck (Na) gene on the sulfur-containing amino acid requirements of broilers.

Full-sibling normal (na/na) and naked neck (Na/na) chickens were fed from 28 to 42 d of age on one of five diets with different SAA contents (from 5.4 to 7.0 g/kg). The experimental diets were made by adding DL-methionine to a well-balanced corn, soybean, and cornstarch diet containing 5.4 g SAA/kg and 161 g crude protein/kg. Dietary SAA influenced the growth rate of both genotypes similarly. There were no significant differences (P > 0.125) in body weight gain due to genetics or a diet by genetics interaction. Body weight gains were maximized at 6.24 +/- 0.45 (R2 = 0.171) and 5.96 +/- 0.52 g/kg SAA (R2 = 0.107) for the na/na and Na/na stocks, respectively. There was a significant SAA by genotype interaction for feed efficiency: the na/na birds were more efficient at low SAA levels, but the Na/na birds were more efficient at high SAA levels. Feather weight gain increased in a linear manner with increasing dietary SAA and was greater in na/na than Na/na birds with high dietary SAA concentrations. Abdominal fat decreased with increasing dietary SAA; and although the Na/na birds had significantly more abdominal fat than their na/na siblings (P = 0.049), on average the difference was small and complicated by differences in body weight. Analysis of covariance showed (a significant interaction) that the relationship between abdominal fat and body weight was different for the na/na and Na/na chickens. Although the shape of the response curves of na/na and Na/na chickens to dietary SAA are different, the quantitative requirements are very similar during the growing period.

Adipose Tissue↗
PubMed1996

Studies on the feeding of cupric sulfate pentahydrate and cupric citrate to broiler chickens.

Male commercial broiler strain chickens were fed either a control diet (based on corn and soybean meal) or the control diet supplemented with cupric sulfate pentahydrate or cupric citrate in seven experiments (six in floor pens, one in wire-floored batteries). In Experiment 1, feeding 125 or 250 mg/kg copper increased growth (4.9%) and decreased feed conversion ratios (3.4%), total plasma cholesterol (40.2%), and breast muscle cholesterol (37.0%). Feeding 375 mg/kg copper was without further beneficial effect. In Experiment 2, withdrawing growth promoting supplements of copper from the feed for the last 7 d caused a significant (P < 0.05) increase in breast muscle cholesterol at 42 d of age: 57.2, 48.0, and 43.2 mg/100 g meat for birds supplemented for 0, 35, or 42 d, respectively. Feeding 10 vs 260 mg/kg copper caused only small increases in tissue copper levels: 0.36 vs 0.41 mg/kg for breast meat, and 0.48 vs 0.60 mg/kg for thigh meat, respectively. Litter copper accumulations in these experiments were similar to those of earlier reports. Breast muscle cholesterol was reduced by feeding 125 mg/kg supplemental copper from cupric citrate (27.84 mg/100 g) or 125 mg supplemental copper from cupric sulfate pentahydrate (25.32 mg/100 g) compared to broilers fed the control diet (43.92 mg/100 g). Cupric citrate was efficacious for growth promotion at lower copper levels than cupric sulfate pentahydrate, resulting in reduced litter copper.

Animals↗
PubMed1995

Dietary copper in excess of nutritional requirement reduces plasma and breast muscle cholesterol of chickens.

Male commercial broiler strain chickens were fed from hatching to 42 d of age either a control diet (based on corn and soybean meal) or the control diet supplemented with 250 mg copper/kg diet from cupric sulfate pentahydrate (for 35 or 42 d). Hypocholesterolemia (11.8% reduction) and decreased breast muscle cholesterol (20.4% reduction) were observed in copper-supplemented birds. There was a slight increase (P > .05) in breast muscle copper (14.5%), and all levels were very low (< .5 mg/kg). Feeding copper for 42 vs 35 d resulted in lower levels of cholesterol in the plasma (12.9 vs 10.8% reduction) and breast muscle (24.6 vs 16.2% reduction). Very similar results were found in two additional experiments in which hypocholesterolemia and reduced breast muscle cholesterol were associated with reduced plasma triglycerides and blood reduced glutathione. It is well known that hypercholesterolemia is a symptom of dietary copper deficiency. The data presented here indicate that blood and breast muscle cholesterol are inversely related to dietary copper in excess of the dietary requirement for maximal growth. The cholesterol content of the edible muscle tissue of broiler chickens can be reduced by approximately 25% after feeding a supranormal level of copper for 42 d without altering the growth of the chickens or substantially increasing the copper content of the edible meat.

Animals↗
PubMed1995

The folic acid requirements of starting broiler chicks fed diets based on practical ingredients. 1. Interrelationships with dietary choline.

Five experiments were conducted to evaluate the effect of dietary supplemental folic acid in starting broiler chick diets. In the first two experiments, basal diets based on corn and soybean meal contained 10 micrograms/kg vitamin B12 but no supplemental methionine or choline. Chicks showed curvilinear responses to folic acid supplementation with maximum growth and feed efficiencies from 1.45 mg/kg diet. The liver folic acid response was also curvilinear but reached a plateau at 1.70 mg folic acid/kg diet. The basal diet for three additional experiments contained soybean meal that had been washed with methanol to remove most of the choline. The basal diet contained only 750 mg/kg choline. Chicks exhibited a larger growth response to folic acid at low choline levels as evidenced by a significant folic acid by choline interaction. Choline and folic acid both increased tibia length and width. Folic acid supplementation increased but then decreased valgus deformity. Choline chloride supplementation also decreased the incidences of valgus and varus deformities and decreased bone ash, but increased the incidence of tibial dyschondroplasia. It is concluded that chicks fed practical ingredient-based diets require 1.3 mg folic acid/kg diet with low levels of choline, but only 1.2 mg folic acid/kg when choline is offered near the NRC recommended level of 1,300 mg/kg of choline.

Animals↗
PubMed1995

The folic acid requirements of starting broiler chicks fed diets based on practical ingredients. 2. Interrelationships with dietary methionine.

Two experiments were conducted to determine the effects of dietary supplemental folic acid and methionine on the performance of starting broiler chicks for 18 d. Four levels of dietary folic acid (.24, .54, 1.14, and 2.34 mg/kg) and four levels of dietary methionine (.45, .53, .61, and .69%) were fed in a factorial design. There were three replicates of eight chicks each per each treatment. The basal diet was based on corn, isolated soybean protein, meat and bone meal, and fish meal. It contained adequate amounts of all nutrients except methionine and folic acid. Increased growth was observed in chicks fed the basal diet supplemented with either folic acid or methionine. Total dietary folic acid and methionine plus cysteine requirements for maximum growth were estimated to be 1.80 mg/kg and .85% in Experiment 1 and 1.47 mg/kg and .87% in Experiment 2, respectively. There were interactions between dietary folic acid and methionine on weight gain in both experiments. Chicks fed the diet containing 2.34 mg folic acid/kg tended to have depressed growth, as in previous experiments. There was a significant linear feed conversion response to folic acid in Experiment 1 and to methionine in Experiment 2. There were both linear and quadratic liver folic acid responses to dietary folic acid in both experiments. There was no indication that dietary methionine had any effect on liver folic acid content. No differences in bone ash, hemoglobin, hematocrit, or incidence of tibial dyschondroplasia were detected due to methionine or folic acid supplementation.

Animals↗
PubMed1995

The magnitude of lead toxicity in broiler chickens.

Four experiments were conducted to study the toxic effects of supplemental dietary lead (Pb) on broiler chickens from hatching to 42 d of age. Dietary variables were 0, 0.1, 0.5 or 1.0 mg Pb/kg feed as lead sulfate in Experiment 1, and 0, 0.5 or 1 mg Pb/kg feed as lead sulfate and lead acetate in Experiment 2. Experiments 3 and 4 were 2 x 4 factorial designs with 2 levels of calcium (0.65% or 1.30%) and 4 levels of Pb (0, 1, 10 or 100 mg Pb as lead sulfate/kg feed). Lead supplementation caused linear decreases in body weight gain in all experiments. In Experiments 1, 2 and 4, even 1 mg added Pb/kg feed caused significantly depressed body gains. Significant negative effects of added Pb on feed conversion ratios were found at 10 mg Pb/kg feed. Supplemental Pb caused a linear decrease in delta-aminolevulinic acid dehydratase (ALAD) activity. The higher level of calcium (1.30%) in the feed significantly reduced the negative effects of Pb on ALAD inhibition. Lead additions to the diet resulted in a dose-related increase of Pb in blood, kidney, liver and tibia. Higher dietary calcium caused reduced Pb in blood and liver. Lead is toxic to chickens at much lower levels than previously recognized.

Animal Feed↗
PubMed1994

Comparative responses of genetically lean and fat chickens to lysine, arginine and non-essential amino acid supply. II. Plasma amino acid responses.

1. Three experiments performed to study the effects of amino acid imbalances on the growth of genetically lean (LL) and fat (FL) male chickens from 28 to 42 d of age were described by Leclercq et al. (1994). The plasma amino acid concentrations of birds on selected treatments from that paper are reported here. In experiment 1, three dietary concentrations of digestible lysine were compared (4.75, 6.75 and 7.75 g/kg). In experiment 2, two dietary concentrations of digestible arginine were compared (6.53 and 10.00 g/kg). In experiment 3, three diets were compared: a high-protein diet (189 g CP/kg), a low-protein diet containing added essential amino acids (144 g CP/kg), and this low-protein diet supplemented with 40 g/kg of non-essential amino acids (NEAA; glutamic and aspartic acids). 2. The present results are compared with two earlier reports on the same genotypes. The LL consistently had lower plasma concentrations of methionine, cystine, phenylalanine, isoleucine and valine, and higher concentrations of histidine, than the FL chickens. In 4 of 5 experiments, LL leucine concentrations were lower, and glutamic acid, tyrosine, glutamine and alanine were higher, than in the FL. The other amino acids measured; arginine, lysine, aspartic acid, glycine and serine, exhibited variable responses among the experiments. 3. When the limiting essential amino acids, lysine and arginine, were added to a deficient diet, the plasma concentration of the supplemented amino acid increased while the others remained constant or decreased. 4. When glutamic and aspartic acids were added to the low protein diet, plasma amino acid responses were similar to those of adding a limiting amino acid to a deficient diet, except that alanine exhibited a dramatic increase. 5. Although there were genotype by diet interactions for several amino acids, the interactions were caused by differences in the degree of the responses, not in their direction. 6. These results suggest that the FL and LL genotypes do not utilise various amino acids with the same efficiency and, as a consequence, the ideal profile of dietary amino acids should not be the same for both lines. The results support the hypothesis that selection for fatness and leanness changed the amino acid requirements independently of the effects of food intake.

Amino Acids↗