Feed Intake In Chickens Research Articles

Effects of feeding growing broiler chickens with practical diets containing sweet lupin (Lupinus angustifolius) seed meal

1. Two experiments with growing broiler chickens were carried out to study the effects of the inclusion in their diets of whole or dehulled lupin (Lupinus angustifolius) seed meal on productive and physiological parameters. The effects of the addition of a commercial protease (1 g/kg, Bio-Feed Pro, Novo. Nordisk, Madrid) were also tested. 2. Diets were formulated to contain the same amounts of energy (12·55 kJ/g) and protein (210 g/kg). Raw whole (not heat treated) or dehulled sweet (low in alkaloids) lupin seed meal (400 and 320 g/kg, respectively) were used to formulate the lupin-based diets, and the protein content was completed with either defatted soybean or casein. 3. Final body weight and feed intake of chickens fed diets containing whole lupin seed meal (400 g/kg) were lower than controls, but gain:feed ratios were not different. The presence of soybean or casein in the diet did not affect productive parameters. Birds fed dehulled (320 g/kg) instead of whole lupin seed meal had similar body weight, feed intake and gain:feed values to controls. The addition of a commercial protease (1 g/kg, Bio-Feed Pro CT) to whole lupin/soy or whole lupin/casein diets tended to increase feed intake and final weight of the birds. 4. Plasma uric acid concentration was higher, and plasma cholesterol and triglycerides lower, in chicks fed whole lupin but not in those fed dehulled lupin seed meal. Plasma amino acid concentrations were not different from controls in birds fed lupin diets. 5. Apparent ileal digestibility of amino acids was not different from controls for the different lupin diets. The relative weight of the liver was higher than controls in lupin-fed birds, but not in those fed enzyme supplemented lupin-based diets. Liver concentrations of DNA tended to rise, while those of glycogen tended to decrease and liver RNA was lower in lupin-fed chicks.

Dietary Energy Source and Supplements in Broiler Diets Containing Defatted Rice Bran

Increasing the concentration of defatted rice bran (DRB) in the diet will increase the concentration of energy sources such as fat (oil) and carbohydrate because DRB contains relatively lower energy compared with the most common energy source, grain (corn). An experiment with broiler chicks was conducted to determine the influence of a high level of fat versus a high level of carbohydrate on the nutritional value of a diet containing 30% DRB. In order to improve the digestibility of fat and to anticipate the negative effect of increasing the concentration of nonstarch polysaccharide in the DRB during the early age of broiler chicks, two supplements [a bile salt (sodium taurocholate) or a fiber-degrading mixture of enzymes (Grindazyme GP 5000)] were included. The protein and fat digestibilities and MEn value were greater with high-fat diets compared with high-carbohydrate diets. These effects of the high-fat diet were reflected in superior growth and feed intake of chicks from 1 to 14 d of age. The supplementation of the DRB diets with the bile salt was of greater benefit for chick performance than the inclusion of a mixture of fiber-degrading enzymes, especially with high-fat diets.

Hepatic tyrosine aminotransferase activity is affected by chronic heat stress and dietary tyrosine in broiler chickens

1. Two experiments were conducted to investigate the impact of high temperature and dietary tyrosine (Tyr) content on performance and activity of hepatic tyrosine aminotransferase (EC 2.6.1.5.), an enzyme that catalyses the first step in the metabolic degradation of Tyr in broiler chickens. 2. Two-week-old birds were allocated to one of three temperature treatments: 24 ° C (control), 36 ° C (heat stress, HS) and 24 ° C pair-fed (24PF) for 2 weeks and fed on diets containing 100% (Experiment 1) and 50, 100 and 200% (Experiment 2) of the NRC requirement for Tyr. 3. In Experiment 1, exposure of chickens to 36 ° C for 2 weeks caused significant increase in hepatic tyrosine aminotransferase activity but no significant change in activity of hepatic phenylalanine 4-hydroxylase (EC 1.14.16.1) (an enzyme that catalyses conversion of phenylalanine to Tyr) compared with the 24PF birds. No significant changes attributable to heat stress were detected in hepatic glutamic-oxaloacetic transaminase (EC 2.6.1.1) activity. 4. In Experiment 2, heat stress caused reductions in weight gain and feed intake in chickens on all diets, compared with their control counterparts. Hepatic tyrosine aminotransferase activity was increased by heat stress compared with their 24PF counterparts in chickens fed on the 100 and 200% Tyr diets, while in chickens fed the 50% Tyr diet, it was reduced by heat stress. 5. From these results, it is suggested that hepatic tyrosine aminotransferase activity is affected by heat stress and dietary Tyr content and the increased tyrosine aminotransferase activity with, in part, relatively low phenylalanine hydroxylase activity in hepatic tissues may be involved in the Tyr metabolism characteristic of heat-stressed chickens.

Pathology and Histopathology of Gossypol Toxicity in Broiler Chicks

Two experiments were conducted to determine the toxicity, pathology, and histopathology of purified gossypol in broiler chicks. Gossypol was added to broiler feed at 0, 100, 200, and 400 mg/kg of feed in Experiment 1 and at 0, 800, and 1600 mg/kg of feed in Experiment 2. Day-old broiler chicks were fed these diets from 1 to 21 days in Experiment 1 and from 1 to 23 days in Experiment 2. In Experiment 1, body weight and feed intake at 21 days were not significantly affected by dietary gossypol. However, chicks fed gossypol at 400 mg/kg of feed had poor feed conversion ratio compared with the other treatment. Feed conversion ratios were 1.493, 1.564, 1.471, and 1.60 for chicks fed gossypol at 0, 100, 200, and 400 mg/kg of feed, respectively (Experiment 1). Chicks fed 400 mg/kg gossypol also had mild perivascular lymphoid aggregate formations and bilary hyperplasia in the liver. In Experiment 2, gossypol at 1600 mg/kg resulted in 28.1% mortality. Gossypol at 800 and 1600 mg/kg feed resulted in significant decreases in body weight and feed intake of chicks. The average body weights of 23-day-old chicks in Experiment 2 were 676, 224, and 111 g for 0, 800, and 1600 mg/kg gossypol, respectively. Feed conversion ratios of chicks fed 800 and 1600 mg/kg gossypol were significantly higher than those of chicks fed control diets (1.383 vs. 1.564 vs. 1.745 for 0, 800, and 1600 mg/kg gossypol, respectively). Plasma iron and hematocrit values were significantly reduced by gossypol at 800 and 1600 mg/kg of feed. Enlarged gallbladder was the only gross pathology symptom associated with gossypol levels. Severe cases of perivascular lymphoid aggregate formation, biliary hyperplasia, and hepatic cholestasis were observed in chicks fed 800 and 1600 mg/kg of gossypol in feed. No gossypol-related changes were observed in kidney tissues of chicks. These results show that gossypol is toxic to broiler chicks at high levels. This study also shows that histopathologic changes in liver due to gossypol also occur at levels lower than the levels that affect body weight.

Effect of Deoiled Jojoba Meal on Feed Intake in Chickens: Satiating or Taste Effect?

Jojoba is an oilseed shrub of the desert. Deoiled jojoba meal represents a potential ingredient for animal feed due to its high protein content. However, a jojoba-rich diet decreases feed intake. This study aimed to discriminate between satiation and palatability effects of jojoba meal in chickens. In a first experiment, broilers did not freely prefer jojoba meal-supplemented feed when they had another choice. A second experiment was based on a model that could differentiate satiety from palatability effects. A satiety factor inhibited feed intake to a lesser degree in fasted than in nonfasted chickens, whereas the reduction in feed intake due to an unpalatable tasting agent was less affected by hunger. When feed was supplemented with jojoba meal, the reduction in feed intake did not differ between fasted and nonfasted chickens. In conclusion, jojoba meal reduces feed intake in chickens by its taste rather than by inducing satiation. Keywords: Jojoba; chickens; feed restriction; taste; satiation

Omeprazole, a Specific Gastric Secretion Inhibitor on Oxynticopeptic Cells, Reduces Gizzard Erosion in Broiler Chicks Fed with Toxic Fish Meals

The relation between gizzard erosion-black vomit (GE-BV) and gastric secretion is not completely understood. A pharmacological approach to reduce the presence of GE-BV in chicks due to fish meal in diets is also unknown. In this study the use of omeprazole, a H +/K + ATPase inhibitor, and fish meals of different biotoxicological characteristics, showed that: 1) Omeprazole decreased total gastric acid content, GE scores and severe GE (SGE) cases, in a dose-dependent manner. This reduction was significant at levels higher than 20 mg omeprazole/Kg body weight (BW)/day ( p < 0.01). The addition of 50 mg omeprazole/kg BW/day almost completely prevented the incidence of SGE cases and reduced in 50% GE score in chicks ( p < 0.01). 2) A significant reduction in specific mortality, near 90%, was also seen with all toxic fish meals when omeprazole (50 mg/Kg BW/day) was added to experimental diets in comparison to control groups. However, no mortality was observed when omeprazole was added to diets containing non-toxic fish meals. 3) In chicks fed with toxic fish meals, addition of different amounts of omeprazole to diets changed the relative weight of proventriculus ( p < 0.01) and gizzard ( p < 0.05). Maximum effect was obtained with omeprazole concentration higher than 50 mg/Kg BW/day. 4) Omeprazole did not change feed intake in chicks fed with toxic fish meal. However, in some fish meal a reduction on weight gain was observed with the addition of omeprazole.

Homoarginine Influences Voluntary Feed Intake, Tissue Basic Amino Acid Concentrations and Arginase Activity in Chickens1–3

Two experiments were conducted to investigate the factors responsible for the adverse effects of guanidinated proteins on feed intake in chickens. In Experiment 1, male broiler chicks were fed one of five purified diets containing casein or guanidinated casein (G-casein) as the sole source of protein (230 g crude protein/kg diet) from d 6 to 13 post-hatching. A casein-based diet containing 17.2 g lysine/kg, served as the control. In the experimental diets, casein was substituted by G-casein and lysine was added at 0, 5.6, 11.4 and 17.0 g/kg diet, respectively. Feed intake and weight gains of chicks fed the G-casein diet without added lysine were markedly depressed (P < 0.05), but this depression was largely overcome by additional lysine. The intake and gains of chicks fed the G-casein diet plus 17.0 g lysine/kg were lower (P < 0.05) than those fed the G-casein diet plus 11.4 g lysine/kg and this was associated with a higher plasma lysine:arginine ratio. Tissue analysis showed that homoarginine is distributed throughout body tissues following absorption. Brain lysine concentrations were lower (P < 0.05) in chicks fed diets containing G-casein without added lysine, but increased (P < 0.05) with supplemental lysine. In Experiment 2, the effect of homoarginine per se on feed intake was investigated in two short-term intake studies using 5-wk-old broiler chickens. Significant (P < 0.05) depressions in feed intake were observed within the first hour after oral administration of 400 mg homoarginine-HCl. The results suggest that both lysine deficiency and homoarginine per se were responsible for the adverse effects of guanidinated proteins on feed intake in chickens.

Effects of raw and treated jack beans(Canavalia ensiformis) and of canavanine on the short-term feed intake of chicks and pigs

SUMMARYFour experiments were conducted in the Yucatán, Mexico, in 1991 and 1992 to study feed intake in 24 h trials with chicks and pigs fed diets containing either raw or treated jack beans or conventional diets with added canavanine.Feed intake of chicks in the first hour was markedly reduced and feed intake of pigs was severely reduced when raw jack beans (300 g/kg for chicks, 250 g/kg for pigs) were included in their diets. Feed intake of pigs diminished to a greater extent than that of chicks when treated beans (300 g/kg) were included in the diet. Short-term feed intake of chicks was not affected when canavanine (3·5 g/kg) was added to a sorghum-soyabean diet. However, pigs showed a large drop in feed intake when canavanine was added to a maize-soya diet at only 0·8 g/kg. It was concluded that in both species the anti-nutritional factors in jack beans cause a rapid reduction in feed intake which precedes a depression in growth rate. The initial feed intake depression in pigs could be partly attributed to canavanine remaining in the jack beans after treatment. In the chicks' case, however, rejection of a diet containing treated jack bean was due to anti-nutritional factor(s) other than residual canavanine.

Effect of enzyme supplementation of wheat and triticale based diets for broilers

The effect of adding 1 g kg −1 of a commercial enzyme preparation (containing β-glucanase, hemicellulase, cellulase and pentosanase activities) to diets containing 300 and 600 g kg −1 of wheat or each of three varieties of triticale (Lasko, Purdy and Proteus) was assessed in a feeding trial with male broiler chicks from 10 to 24 days of age. Also the TMEn value of diets was determined using adult cockerels. At inclusion rates of 300 or 600 g kg −1 the TMEn (true metabolizable energy) values and the productive responses of chicks (feed intake, weight gain and feed efficiency) were similar for all four cereals, except that the weight gain for triticale Proteus at 300 g kg −1 was lower ( P < 0.05). Increasing the content of cereals from 300 to 600 g kg −1 improved the TMEn of the diets ( P < 0.05) and decreased the feed intake ( P < 0.05), but did not affect the weight gain of birds, except the diet with triticale Proteus which decreased ( P < 0.05). These results confirm that the nutritive value of some cultivars of triticale (i.e. Lasko and Purdy) for birds is similar to that of wheat, and that these varieties can be used at high inclusion rates in poultry diets. The enzyme supplementation of diets did not modify their TMEn value or feed intake of chicks, but the enzyme preparation improved ( P < 0.05) feed efficiency of all diets and weight gain at the highest rate of inclusion of triticales. In this study, the best results with enzyme supplementation were obtained with the cereals with lowest nutritive value and when the inclusion rate of cereals was the highest.

Genetic Control of Food Intake in Chickens

Genetic selection for body weight in broiler-type chickens has created a highly efficient omnivore capable of attaining a 2.0 kg body weight in 40-42 d of age with an overall feed conversion (feed consumed per unit of body weight) of less than two. The primary correlated response to the huge increases in the growth of chickens over the last 50 years has been increased feed intake. Although there is much independent data regarding the physiological systems controlling feed intake, there is a dearth of information regarding the inheritance of central and peripheral feed intake control mechanisms. Using four lines of chickens from a double selection experiment for exponential growth rate at different ages, we are investigating changes in both peripheral and central feed intake control mechanisms in response to selection. We have observed a genetic basis for neurotransmitter levels in the hatching chick, which seems to be related to selection for body weight. Diallel crossing experiments have demonstrated that catecholamine levels are inherited in a nonadditive manner, as is feed consumption immediately post-hatch, suggesting that sympathetic nervous activity (as defined by catecholamine and metabolite levels) may be involved in the inheritance of early feed intake in chickens. Further, the use of pharmacological substances (such as monosodium glutamate) known to alter food intake in mammals exhibit signs of genotype by treatment interactions for growth and hypothalamic neurotransmitter levels. These data suggest a research strategy to separate genetic changes in food intake from those related to responses in metabolism.

Evaluation of the effect of extrusion cooking of jackbean ( Canavalia ensiformis L.) seed on short-term feed intake in chicks

Experiments were conducted to investigate the relationship between various extrusion cooking conditions, the chemical composition of jackbean samples and the short-term control of food intake in chicks. All data were analysed using a principal component analysis computerized program. Ground jackbean was extruded on a pilot-scale twin-screw extruder. Water addition at the feed inlet, filling rate of the screws, barrel temperature in the last section of the extruder and reverse-screw element position were tested as operating variables. Three sets of experiments (A, B and C) and a total of 20 trials were performed. Process variables were specific mechanical energy, product temperature measured at the die and resulting pressure exerted on the shafts. Also, colour values were determined on all jackbean samples. Experimental diets containing 300 g kg −1 extruded jackbean were fed to 7-day-old chicks to measure the short-term variations in food intake. Inactivation of the lectin (concanavalin A) was monitored using a haemagglutination assay. In addition, starch solubility, and reactive lysine and canavanine contents were determined on samples from Experiment A. Pilot-scale extrusion cooking of Canavalia appears to be feasible: water addition decreased energy consumption ( r = −0.76), filling rate and position of the reverse-screw element are correlated to product temperature ( r = +0.61 and −0.66, respectively). Food intake inhibition index, used as an expression of toxicity for chicks, was reduced in proportion to a decrease in the amount of water added and to the filling rate ( r = +0.8 and +0.6, respectively). The minimum food intake inhibition index was 70% in Experiment A, 61% in Experiment B and 35% in Experiment C according to our experimental conditions. The lower the food intake inhibition index, the more delayed the inhibition effect on food intake. Lightness and specific mechanical energy appeared to be accurate indicators of the detoxification level ( r = +0.85 and +0.72). No significant relationship was apparent between toxicity and haemagglutination activity of the meal. Additional research is needed to understand the high correlation found among canavanine, reactive lysine content and the reduced feed intake shown by the chicks.

The effect of fat level and type on the utilization of triticale (cultivar Carman) by broiler chicks

Two experiments were conducted with broiler chicks to compare diets based on Carman triticale and Glenlea wheat, supplemented with 2 fat levels (4 and 6% animal tallow) and 2 fat types (animal tallow vs. sunflower oil). In Experiment 1, wheat- and triticale-based diets were supplemented with 4 and 6% fat. No response in feed consumption to the different fat levels was detected. However, the feed intake of chicks was higher for triticale diets than for wheat diets ( P < 0.01). Addition of 6% fat resulted in a slight (non-significant) increase in body weight gain of chicks given either wheat or triticale. Triticale diets gave a poorer ( P < 0.01) feed:gain ratio. No response to higher fat level in feed:gain ratio was observed for the triticale diet, but a slight improvement was obtained with the wheat diet ( P < 0.05). In Experiment 2, wheat- and triticale-based diets were supplemented with 2 fat types (animal tallow vs. sunflower oil). Results obtained for feed consumption were similar to those obtained in the first experiment. Supplementing either diet with sunflower oil significantly ( P < 0.05) improved chick weight gain. No response to the grain type, and no grain type × fat type interaction was apparent. The triticale diets gave a poorer ( P < 0.01) feed:gain ratio. Replacing tallow by sunflower oil significantly ( P < 0.01) improved feed:gain ratio for both grains. Differences in mortality were small and non-significant in both experiments. The results of this study show that the performance of chicks fed on Carman triticale diets was not affected by fat level, but chick growth and feed:gain ratio responded to fat type.

Effect of Decreased Feed Intake on Serum and Pancreatic α-Amylase of Broiler Chickens

Removal of feed from 20-day-old broiler chicks for 24 hours caused serum and pancreatic alpha-amylase activities to increase almost twofold. A 24-hour feeding period following feed removal caused a reduction in serum alpha-amylase to basal levels and a sixfold reduction in pancreatic alpha-amylase activity. Serum alpha-amylase levels remained elevated after long-term feed restriction in adult broilers compared with levels in full-fed controls. Reduction in feed intake in chicks caused by coccidial infections also resulted in increased serum alpha-amylase. In all cases, the degree of change in serum alpha-amylase corresponded inversely to feed intake. It is proposed that the pancreas synthesizes a specific quantity of alpha-amylase, which does not change even under conditions of extended underconsumption of feed. The rate of alpha-amylase secretion is determined, at least indirectly, by the rate of carbohydrate metabolism, and the remainder of the enzyme is stored in the pancreatic cells. A small percentage of the stored enzyme diffuses into the blood and thus directly reflects increased secretion or accumulation of alpha-amylase in the pancreas in response to conditions of carbohydrate utilization.

鶏の十二指腸と腹腔へのグルコース注入が飼料摂取へ及ぼす影響

鶏の十二指腸と腹腔へのグルコース注入が飼料摂取へ及ぼす影響

Available phosphorus in poultry. 2. Effect of phosphorus in diet on performance of chicks, bone composition and strength, and calcium and inorganic phosphorus in blood plasma.

2. In 2 trials, medium heavy laying hens were crossed with White Cornish (Hybro) cocks to produce 2160 male chickens which were kept in batteries and given a diet with 0.3, 0.5 or 0.7% available phosphorus. Bodyweight, growth and feed intake of chickens 3 or 7 weeks old increased with increasing amounts of available P. Efficiency of feed conversion did not differ at 7 weeks old but was improved in chickens given 0.7% P at 3 weeks. Calcium and inorganic P in plasma and breaking strength, ash and P in the tibia increased with increasing P in the diet. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The effect of intrahypothalamic administration of sodium pentobarbital on eating behaviour and feed intake in chickens

Injection of sodium pentobarbital solutions were carried out in chickens, through permanently implanted cannulas in the brain. Chickens with cannulas implanted in the third ventricle, above the hypothalamic ventromedial area, responded with immediate increase in feed intake and vigorous pecking behaviour which lasted from 10–60 min. Chickens with cannulas implanted in the posterior lateral hypothalamus showed no changes in their feed intake or eating behaviour after sodium pentobarbital injection. The results with chickens correspond to those obtained with rats, cats and dogs.

Feeding Behaviour Elicited by Electrical Stimulation of the Brain in Chickens, Gallus Gallus

In a search for the neural mechanisms that regulate feed intake in chickens, 625 sites in the anterior hypothalamus and supra- and pre-optic areas of the brains of sixty-eight chickens were stimulated through chronically-implanted electrodes. Feeding behaviour was elicited reliably from only six sites, and none of these led to feeding on the normal feed (mash) during stimulation.

Biological Assay of Available Energy with Growing Chicks

Influences of dietary protein level, length of experimental period, difference in breeds of chicks and seasonal variation were evaluated on the data obtained by biological assay of available energy in feedstuffs with growing chicks.1. Effect of dietary protein levelMathematical analyses of the relationship between body weight gain and dietary levels of energy and protein revealed that the protein level of the reference diets for biological assay of available energy with day-old and 4-week-old chicks should be kept about 23% and 21%, respectively. Small variation of dietary protein level was expected to have little influence on the result of the bioassay.Three diets containing 19, 21 and 23% of protein with constant energy level were fed to chicks of 4-week-old chicks for 4 weeks in Expt. 509. Growth rate of chicks on these diet were almost identical, suggesting that the mathematical considerations is reliable. Therefore, available energy of feedstuffs containing protein can be estimated by directly replacing cornstarch in the reference diet, provided the increase of dietary protein level by this replacement is less than 2%.2. Effect of length of experimental periodAvailable energy of test diets (x) can be estimated from the weight gain (y) of chicks on the diet with the equation (1), where a is constant, b regression coefficient, r correlation coefficient, Syy and Sxx sum of squares of y and x, respectively. These figures are estimated with the data on reference diets. n and p in this equation are numbers of lots of chicks fed the reference and test diets, respectively. tα(n-2) is t-value in t-tablex=(y-a)/b±tα(n-2)•√Syy(1-r2)/n-2•√1/n+1/p+(x-x)2/Sxx/b……(1)with probability of α and (n-2) degrees of freedom. Therefore, the bigger the n, p and b are, and the closer to 1 the γ is, the smaller fiducial limit for the estimate x is expected.In Table 3, length of experimental period, b, 95% fiducial limit for b, r and 95% fiducial limit for x were summarized. It is suggested that 4 weeks of experimental period is necessary to get satisfactory result of bioassay, when starting chicks are used. This is because of the smaller b and r, and therefore, larger fiducial limit for x is obtained with experimental period shorter than 4 weeks. Two weeks of experimental period were shown to be quite satisfactory with 4-week-old chicks. At the slight sacrifice of thee accuracy of the estimate, the period could be as short as 1 week.Bioassay with starting chicks has an advantage of estimation without regard to the difference in feed intake of chicks, while bioassay with older chicks has a merit of a shorter experimental period.3. Difference in breeds of chicks and seasonal variationIn Table 4, b value, i.e. the change of body weight gain per unit change of dietary energy level, of various pure- and crossbred chicks were compared. No significant difference in b value was observed among the different breeds. No consistent seasonal variation of b was obtained in various experiments conducted in different seasons.