Effects of group size on the feeding behaviour and growth of chicks

1. The aim of the study was to see if social facilitation of feeding has a lasting effect on the growth of chicks.

2. In two experiments, newly hatched hybrid and Brown Leghorn chicks were reared in isolation and in small groups of different sizes, and their growth, food intake and feeding activity were measured for several eeks.

3. Initially, chicks of both strains grew faster when they were grouped than when they were in isolation, as a result of a more efficient conversion of food rather than as a result of increased consumption.

4. Later, chicks in the largest groups converted their food less efficiently, possibly because of increased disturbance.

5. From 6 to 12 weeks, when the chicks were in larger cages, growth rate was not affected by group size, but food intake and food conversion were affected differently in the two strains.

6. In general, the isolated chicks ate about the same amount as the grouped ones, and it is doubtful whether social facilitation of feeding occurred at all in these experiments.     

Recycled dried poultry manure in chick starter diets

1. Dried poultry manure (DPM) collected from 1‐d to 3‐week‐old chicks, reared in electrical battery brooders, incorporated at a level of 0, 5, 10, 15 and 20% in a chick starter diet, was recycled four times.

2. There was a linear decrease in body weight and efficiency of food utilisation with each percentage increase in DPM.

3. The amount of dried droppings recovered as a percentage of food consumed was proportional to the amount of DPM included in the diet and remained fairly constant during the recycling.

4. Body weights and efficiency of food utilisation were substantially the same during the first three recycling periods but declined significantly during the fourth period.

5. Mortality was negligible and all chicks appeared healthy and vigorous.

6. Chicks fed on 10% DPM in an isocaloric and isonitrogenous (protein‐N) diet grew and utilised food as well as those fed on the basal diet; chicks fed on 20% DPM did not consume enough to meet their requirements.     

Effects of dietary supplements on the nutritive value of jack beans (canavalia ensiformis) for the young chick

1. Two experiments were conducted with young chicks to examine the efficacy of dietary supplements of amino acids, creatine and potassium acetate in the alleviation of adverse effects of auto‐claved jack beans (AJB).

2. Creatine supplementation of AJB diets markedly enhanced the efficiencies of food and nitrogen utilisation of chicks, restoring these indices to control values. The improvement in nitrogen utilisation was enhanced further on providing creatine with a mixture of 2‐aminoiso‐butyric acid, arginine and lysine.

3. Potassium acetate induced striking improvements in the nitrogen retention efficiencies of chicks fed on AJB diets.

4. Liver weights, as a proportion of body weight, generally increased on feeding AJB diets, the effects being marked with the AJB diet supplemented with arginine and lysine.

5. Hepatic urea concentrations were elevated in all groups receiving AJB. Canavanine, a toxic amino acid component of AJB, could not be detected in acid hydrolysates of livers from chicks fed this legume.

6. Temperature and the volumes of water employed in the preparation of AJB are important determinants of its nutritional value.     

Feeding and pecking behaviour in ostrich (Struthio camelus) chicks in captivity

1. Three sets of experiments were performed on two batches of ostrich chicks to investigate the factors affecting the pecking and feeding behaviour of grouped individuals.

2. Chicks showed no significant alteration of their feeding behaviour in response to raising pen walls in the rearing facility from 30 to 60 cm.

3. Further analysis on a different set of birds revealed consistent short term individual differences in the frequency of feeding and non‐feeding pecks.

4. There were significant pen effects on behaviour suggesting the possible development of a pen ‘culture’ of pecking behaviour.

5. Pecking behaviours in 26 to 33 d‐old chicks, with the exception of drinking, were generally negatively correlated, so any non‐food pecking by a chick was generally associated with fewer pecks targeted at food.

6. By the age of two months chicks were pecking at food on the floor to a far greater extent than at any food presented in food trays.     

The contribution of anorexia to reduced growth in zinc‐deficient chickens

1. It was shown, using a paired‐feeding technique, that the growth depression in zinc‐deficient chicks was largely caused by the greatly reduced consumption of the deficient diet.

2. Chicks receiving a zinc sulphate solution directly into the crop ate an amount of zinc‐deficient diet similar to that of the zinc‐sufficient diet eaten by the control chicks; palatability was thus ruled out as the cause of the anorexia.

3. Only chicks receiving the zinc‐deficient diet displayed signs of zinc deficiency.     

Effect of diets containing raw and extrusion‐cooked rice bran on growth and efficiency of food utilization of broilers

1. Meat strain chicks were fed on diets containing 600 g rice bran/kg for the 7 to 8 week period required to reach broiler weight.

2. Extrusion cooking of rice bran resulted, in improved chick weight gain and food efficiency for the first two weeks of feeding, but this advantage was lost by the end of the feeding period.

3. Addition of 10 g calcium/kg to the stabilised rice bran diet prevented the decline in performance after two weeks of age, and birds fed on this diet continued to gain at an increasing rate until the end of the experiment.

4. Calcium supplementation of stabilised rice bran diets produced significantly greater gains and superior food utilisation compared to stabilised rice bran diets without added calcium.

5. Calcium supplementation did not affect weight gain of chicks fed on diets containing raw rice bran.

6. Taste panel evaluation of meat from birds fed on diets containing raw rice bran, stabilised rice bran, or no rice bran indicated a significant preference in only one combination tested. Any ‘off flavour could not be related to dietary treatment.     

Tissue content of α‐tocopherol and oxidative stability of broilers receiving dietary α‐tocopheryl acetate supplement for various periods pre‐slaughter

1. The effects of dietary α‐tocopheryl acetate on the α‐tocopherol status of chicken plasma and tissues were investigated. The rate of iron‐ascorbate‐induced lipid peroxidation was also studied.

2. One hundred and forty four chicks were divided into 6 groups: one control group was fed a basal diet of 30 mg α‐tocopheryl acetate/kg food for the duration of the trial. A supplemental diet of 200 mg α‐tocopheryl acetate was fed to each of the odier 5 groups for 1,2,3,4 or 5 weeks prior to slaughter.

3. Supplementation resulted in an increase in α‐tocopherol in plasma and all tissues examined. Saturation levels of α‐tocopherol were observed in plasma after 1 week of feeding and in tissues within 3 to 4 weeks of feeding.

4. Supplementation with α‐tocopheryl acetate for up to 4 weeks pre‐slaughter resulted in significant reductions in susceptibility to induced lipid peroxidation.

5. Overall, the results show that feeding 200 mg α‐tocopheryl acetate/kg food to chicks for at least 4 weeks prior to slaughter is necessary to optimise muscle content and stability against lipid peroxidation.     

The nutritional value of low lathyrogenic Lathyrus (Lathyrus sativus) for growing chicks

1. The feeding value of new low β‐N‐oxalyl‐amino‐L‐alanine (BOAA) lines of Lathyrus sativus (lathyrus) and the benefits of dehulling the seed or of pre‐adapting chicks to lathyrus‐based diets were examined in several experiments.

2. Chicks fed on diets containing 400 g/kg of the low (1.3 g BOAA/kg seed) and medium (2.2 g BOAA/kg seed) BOAA lines did not differ (P>0.05) in weight gain (WG) or in apparent fat and protein digestibilities compared to birds fed on a wheat‐based diet.

3. Consumption of 600 g low BOAA lathyrus/kg diet caused a slight, but significant (P< 0.05), decrease in WG. Food efficiency decreased as the amount of dietary lathyrus was increased, suggesting that lathyrus may contain an antinutritive factor(s) other than BOAA.

4. Removal of the hull (70 g hull/kg seed) from the seed did not affect chick performance (P> 0.05).

5. Pre‐adapting chicks for 7 d to diets containing up to 600 g medium line lathyrus/kg diet did not reduce the detrimental effects of the lathyrus.

6. Although dehulling and pre‐adaptation of chicks to lathyrus were not beneficial, the low and medium lines of lathyrus tested show potential for use in chick diets up to at least 400 g lathyrus/kg diet.     

Immunoresponsiveness of fast‐growing chickens as influenced by feeding regimen

1. Immunoresponsiveness and disease resistance were measured in broiler males maintained on ad libitum feeding throughout or on alternate‐day feeding. Alternate‐day restrictions were started 1 and 2 d after hatch so that on any one day there were chicks fed and fasted.

2. Severity of response to E. coli challenge as measured by lesion scores, and mortality was greater for chicks fed ad libitum than those fed on alternate days. For chicks fed on alternate days, lesion scores were lower for those without access to feed for the 24‐h period immediately after challenge.

3. Spleen weights, the indicator of response to marble spleen disease virus challenge, were higher for chicks fed ad libitum than those fed on alternate days.

4. Antibody response to sheep red blood cell antigen was not affected by feeding regimen.

5. Ratios of heterophils to lymphocytes were higher for chicks given access to feed for the previous 24‐h period than for those fasted during the previous 24‐h or those that had been fed ad libitum.

6. Results of this experiment suggest that for alternate‐day feeding programs, vaccination be administered on the day that chicks are not fed.     

Growth related traits in body weight selected lines and their crosses reared under different nutritional regimens

1. Four populations—two that had undergone 37 generations of selection for high (HH) and low (LL) body weight, and reciprocal crosses between them (HL and LH) were fed two diets differing in protein and energy. Diet A, under which selection had been made, contained 200 g protein and 11.23 MJ/kg. Diet E contained 240 g protein and 13.16 MJ/kg.

2. Body weight and feed efficiency were measured weekly from hatch to 56 d of age at which time oesophagus, abdominal fat pad, heart, liver and lungs were removed and weighed. At 35 d of age chicks were inoculated with sheep erythrocytes (SRBC) and antibody titre was measured 6 d later.

3. Chicks fed diet E were heavier than those fed diet A. HH chicks were heavier dian LL chicks wim HL and LH chicks intermediate to the parental lines. LH chicks were heavier than HL ones reflecting large maternal effects.

4. Food efficiencies among stocks and diets were consistent with those for body weight, with HH > LH > HL > LL and E > A. Relative differences between diets were similar across ages and heterosis for food efficiency was about 15%.

5. Relative to body weight, oesophagus and liver weights were heavier in chickens fed diet A than fed diet E. The pattern reversed for abdominal fat pad.

6. Antibody to SRBC antigen was greater in the crosses than in line HH and in cross HL than line LL, with heterosis of 70%.     

Effect of autoclaving,hot‐water treating,parboiling and addition of ethoxy‐quin on the value of rice bran as a dietary ingredient for chickens

1. Three experiments of 3 or 4 weeks’ duration were conducted with broilers fed on diets containing 60% of rice bran treated in various ways.

2. Autoclaving rice bran for 3 to 20 min significantly improved its feeding value as measured by growth rate of chicks; bran from parboiled rice was equivalent to the autoclaved rice bran and was not further improved by autoclaving.

3. The growth inhibition of rice bran is not due to its trypsin inhibitor activity.

4. Lipase activity in rice bran was destroyed by autoclaving or parboiling and may be a useful index to predict the adequacy of treatment to improve growth.

5. The metabolisable energy of the rice bran samples was about 12.55 kJ/g and was not influenced by treatment.

6. Ethoxyquin did not improve growth of chicks fed on diets containing rice bran and was less effective than autoclaving or parboiling in preventing the development of rancidity.     

Genotype‐level of protein interaction for growth rate in broilers

1. Two groups of White Plymouth Rock which were related to each other as half‐sibs were fed on diets containing either a normal or reduced amount of protein.

2. Compared with the normal diet the low‐protein diet caused a decrease in growth rate which at 38 d was 37% and 25% for male and female chickens, respectively.

3. A genotype‐level of protein interaction was demonstrated for weight at 38 d. Expressed as a genetic correlation for the same trait and measured in the two feeding environments the values were about 0.33.

4. In estimating the genetic correlation the interaction as well as the covariance method were used. The two methods did not give the same estimates.

5. Heritabilities for weight at 38 d tend to be larger in the low‐protein environment.     

Studies on the toxic effects of crambe meal and two of its constituents, 1‐cyano‐2‐hydroxy‐3‐butene (GHB) and epiprogoitrin,in broiler chick diets

1. Studies were undertaken to determine a safe inclusion rate for crambe (Crambe abyssinica) meal in broiler chick diets, and to determine the mechanism for adverse effects by investigating its constituents; l‐cyano‐2‐hydroxy‐3‐butene (CHB) and 3‐butenyl glucosinolate (epi‐progoitrin, E‐PG).

2. Crambe meals were prepared to differ in E‐PG (19, 36 and 40 g/kg) and CHB contents (0.1, 0.7 and 1.9 g/kg), and with either active or inactive thioglucosidase.

3. Meals were fed to 7‐d‐old broiler chicks at 50 or 100 g/kg of the diet for 12 or 13 d. In separate studies, isolated E‐PG or CHB were mixed into the diet or administered by gavage to 7‐d‐old broiler chicks in amounts equivalent to 50 or 100 g/kg crambe meal diets for 10 and 12 d, respectively.

4. Weight gain decreased (P<0.05) in chicks fed on the high glucosinolate crambe diets or isolated E‐PG. Food consumption decreased (P<0.05) in chicks fed on the diet containing the high E‐PG meal with active enzyme.

5. Mild liver lesions and increased serum aspartate aminotransferase were found in chicks fed on the diet containing the high glucosinolate meal with active enzyme. Other organs, including thyroids, were normal.

6. Commercially‐processed crambe meal appeared safe at an inclusion rate of 50 or 100 g/kg diet, but could not be recommended at this point for long term feeding.     

A purified diet for one‐day‐old chicks

1. In each of four experiments 140 or 160 1‐d‐old broiler chicks were fed for 14 d on diets based on crystalline amino acids and other purified ingredients. The basal diet was a purified diet found suitable for 7‐d‐old chicks.

2. Growth was poorer with the basal diet than with a practical diet and it was not improved by an increase in the concentration of vitamins or supplementation with isolated soy protein, water or liver.

3. An increase in the amount of mineral mixture or of magnesium alone gave a significant improvement in growth, so that it approximated that obtained with the practical diet. Food conversion efficiency was significantly better with the mineral‐supplemented than with the practical diet.

4. The basal purified diet supplemented with magnesium to provide 684 mg Mg per kilogram was satisfactory for the early growth; chicks fed on this diet did not respond to sources of “unidentified factors” such as fresh or freeze‐dried liver and soy‐protein.     

Lysine requirement of broiler chicks as affected by protein source and method of statistical evaluation 1

1. An experiment was designed to test if the lysine requirement, expressed as g lysine/kg CP, was the same for several protein sources.

2. Groundnut meal, groundnut meal adjusted with indispensable amino acids or sesame meal supplied the dietary CP at 180 g/kg diet. Increments of lysine (1.5 g/kg diet) were added to each of these diets.

3. The gain, food intake and food efficiency responses of broiler chicks were analysed using a quadratic equation and a two‐slope method. An estimate of lysine requirements was also obtained from a survey of college students.

4. The different methods produced widely different estimates of lysine requirement.

5. The average lysine requirement was estimated at 50.1 g lysine/kg CP for groundnut meal, 61.7 for adjusted groundnut meal and 54.9 for sesame meal.

6. Reasons for the effect of statistical analysis and protein source on lysine requirement are discussed.     

Performance of broiler chicks fed on alkali‐treated neem (Azadirachta indica) kernel cake as a protein supplement

1. An experiment was conducted to evaluate growth and nutrient efficiency of broiler chicks from 3 to 42 d fed on diets containing alkali‐treated neem (Azadirachta indica A. juss) kernel cake (NKC) as a protein supplement in place of peanut meal (PNM).

2. NKC was treated with sodium hydroxide at 10 (ANKC 1) or 20 g (ANKC 2)/kg and incorporated into the test diets at 135 or 300 g/kg to replace 50 (low—L) or 100 (High—H) % of the PNM protein of the reference diet.

3. Despite comparable retentions of dry matter and total carbohydrate on L‐ANKC 1 and 2, fibre on L‐and H‐ANKC 2 and nitrogen, calcium and acid detergent fibre on all experimental diets compared to the retentions of chicks on the reference diet, only the chicks fed L‐ANKG 2 were found to grow and utilise food as well as those on the reference diet.

4. The activities of serum alkaline phosphatase on H‐ANKC 1 and alanine amino transferase on all test diets were depressed (P < 0.05), but the activity of serum aspartate amino transferase, total erythrocyte count and concentration of blood haemoglobin and urea were similar in all chicks.

5. No significant differences were noticed in the qualitative and quantitative characteristics of the meat of chicks fed on the reference diet and on diets incorporating ANKC at the lower concentrations. Feeding ANKC protein did not impart any untoward taste as evaluated in pressure cooked meat by a semitrained panel on a 7 point Hedonic scale.

6. Except for duodenal and jejunal inflammation in chicks on both reference and test diets, all the vital organs were normal, ruling out any adverse affects caused by residual neem bitters.

7. Comparable performance and cost of chicks fed on the reference and L‐ANKC 2 diets, warrants the utilisation of hitherto wasted protein‐rich NKC after alkali treatment in broiler chick diets to spare peanut meal for human consumption in developing countries.     

The nutritional value of salseed (Shorea robusta) meal for growing chicks

1. Salseed meal contains 98 g crude protein, 22 g ether extractives, 450 g available carbohydrate and 117 g tannins per kg.

2. From the chemical analysis the metabolisable energy (ME) content of salseed meal would be expected to be 11.22 MJ/kg. In vivo assay with chicks yielded values considerably less than this, 7.1 MJ/kg being found at an inclusion rate of 150 g/kg diet.

3. As the inclusion rate of salseed meal was increased to 300 g/kg, dietary ME and the digestion and retention of dietary protein decreased.

4. More than 50 g salseed meal/kg in the diet of chicks resulted in poor growth rate and food conversion.     

Effects of a beta‐adrenergic agonist clenbuterol) on performance,carcase composition,hepatic microsomal mixed function oxidase and antibody production in female broilers treated with or without corticosterone

1. Beta‐adrenergic agonist (Clenbuterol, 0.33 mg/kg) and corticosterone (10 mg/kg) were incorporated into a diet based on maize and soyabean meal. Their effects on performance, carcase composition, hepatic microsomal mixed function oxidase and antibody production were investigated in female broilers.

2. Dietary corticosterone reduced the titre to sheep red blood cells, while it was unchanged by clenbuterol.

3. Clenbuterol exerted a promoting effect on gain‐to‐food ratio, carcase protein and hepatic microsomal cytochrome P‐450 content.

4. Addition of clenbuterol to the corticosterone‐containing diet prevented the increase in abdominal fat weight and uric acid excretion induced by corticosterone, but did not affect total fat mass.

5. The results showed that clenbuterol reduced abdominal rather than carcase fat and prevented protein degradation in the body when chicks were treated with corticosterone. Clenbuterol also influenced the content of cytochrome P‐450, but not the humoral immunity.     

Effects of partially hydrolysed guar gum on feeding behaviour and crop emptying rate in chicks

1. The effects of partially hydrolysed guar gum (PHGG) or intact guar gum (GG) on feeding behaviour and crop emptying rate in growing chicks were investigated.

2. Several combinations of dietary PHGG and GG at 50 g per kg diets were prepared for a feed intake experiment. Birds (17‐d‐old) were given diets for 3 h after 16 h fasting, and food consumption was measured at 1 h intervals. The food intake rapidly decreased as the dietary GG content increased even at 1 h after feeding.

3. The rate of food passage from the crop was also investigated with birds (20‐d‐old) after 16 h fasting. Birds were tube‐fed diets having several ratios of dietary PHGG and GG. After 1 h of feeding, the diet remaining in the crop was measured after drying. The crop emptying rate decreased linearly as dietary PHGG concentration decreased.

4. The present study suggests that partial hydrolysis of dietary GG improve both feeding behaviour and food passage from the crop in growing chicks.     

Antimicrobial substances and chick growth promotion: The growth‐promoting activities of antimicrobial substances,including fifty‐two used either in therapy or as dietary additives

1. Fifty‐five antimicrobial substances were tested for their ability to promote growth when added to the diet of chicks.

2. Both cephalosporins and all the nine penicillins tested were active.

3. Of six aminoglycosides, streptomycin and gentamicin had the greatest activity and neomycin had none.

4. Growth rate was significantly improved by clindamycin, lincomycin, vancomycin, spectinomycin, rifampicin, oxytetracycline, chlortetracycline, erythromycin, tylosin, flavomycin, virginiamycin and zinc bacitracin. Chloramphenicol and nalidixic acid were inactive. Polymixin B, novo‐biocin, cycloserine, phosphonomycin, and sodium fusidate had little activity. Fusidic acid promoted growth at 250 mg/kg diet.

5. Trimethoprim was inactive alone and in combination with sulpha‐diazine. Of seven 5‐nitroimidazoles, only dimetridazole and metronidazole showed slight activity. Of the six 5‐nitrofurans, only nitrovin, the standard reference substance used, promoted growth.

6. Caprylohydroxamic acid, a urease inhibitor, had no beneficial effect on growth rate or on the efficiency of food conversion.

7. The growth‐promoting properties of the various substances could not be related with their known antimicrobial and absorption characteristics in mammals.