Influence of graded levels of meals from three lupin species on growth performance and nutrient digestibility in broiler chickens

1. This study investigated the effect of different levels of seeds of lupin species (Lupinus angustifolius, Lupinus luteus and Lupinus albus) on broiler growth performance, nutrient digestibility and apparent metabolisable energy of poultry diets.

2. A control diet containing corn–soybean meal and test diets containing 50, 100, 150, 200 and 250 g/kg of three lupin species were fed to broiler chickens during a 35-day study period. There were 10 replicate cages of 8 broiler chickens per treatment.

3. Growth performance of the birds fed with yellow and white lupin diets was found to be similar to that of the birds in the control group. The use of narrow-leaved lupin seeds in the diet quadratically decreased the body weight gain of birds and increased feed conversion ratio during all the experimental periods (0–14, 15–35 and overall 0–35 days of age).

4. A significant interaction between lupin species and their inclusion levels for apparent metabolisable energy and apparent ileal digestibility of starch was observed, showing a negative effect of increasing levels of narrow-leaved lupin. Pearson correlation coefficients demonstrated that the presence of raffinose and non-starch polysaccharides is a key factor affecting the nutritive value of lupin,

5. Yellow and white lupins could be utilised as an alternative ingredient for soybean meal in the diet of broiler chickens without any adverse effects on growth performance. The narrow-leaved counterpart diet reduced broiler performance, and hence did not provide a satisfactory outcome.     

Immune-modulatory effects of dietary Saccharomyces cerevisiae cell wall in broiler chickens inoculated with Escherichia coli lipopolysaccharide

1. An experiment was conducted to study the effect of yeast (Saccharomyces cerevisiae) cell wall (YCW) supplemented in diets of broiler chickens challenged with Escherichia coli lipopolysaccharide (LPS).

2. One-day-old broiler chicks were randomly distributed into 24 cages (6 replicate cages; 8 birds/cage) and were inoculated with 0 or 1 mg/kg body weight E. coli-LPS (d 4 and 9) and 0 or 500 mg YCW/kg feed, resulting in a 2 × 2 factorial arrangement of treatments. Experimental diets did not include coccidiostats, in-feed antibiotics or enzymes.

3. On d 21, the inoculation of E. coli-LPS reduced weight gain and feed intake and increased feed conversion ratio (FCR) of birds, an effect maintained until 28 d. In contrast, chickens given diets with YCW improved the FCR at both 21 and 28 d of age.

4. E. coli-LPS challenge reduced the relative weight of bursa of Fabricius, except when chickens were given YCW, which resulted in an interaction. Supplementation of broiler diets with YCW exacerbated the cellular immune response as measured by the delayed cutaneous hypersensitivity response test.

5. The results of this study suggested a benefit on feed efficiency when YCW was added to diets fed to broiler chickens challenged with E. coli-LPS. Part of the mode of action of YCW might be related to better maintenance of immune status in response to microbial challenge.     

Broiler weight estimation based on machine vision and artificial neural network

1. Machine vision and artificial neural network (ANN) procedures were used to estimate live body weight of broiler chickens in 30 1-d-old broiler chickens reared for 42 d.

2. Imaging was performed two times daily. To localise chickens within the pen, an ellipse fitting algorithm was used and the chickens’ head and tail removed using the Chan–Vese method.

3. The correlations between the body weight and 6 physical extracted features indicated that there were strong correlations between body weight and the 5 features including area, perimeter, convex area, major and minor axis length.

5. According to statistical analysis there was no significant difference between morning and afternoon data over 42 d.

6. In an attempt to improve the accuracy of live weight approximation different ANN techniques, including Bayesian regulation, Levenberg–Marquardt, Scaled conjugate gradient and gradient descent were used. Bayesian regulation with R² value of 0.98 was the best network for prediction of broiler weight.

7. The accuracy of the machine vision technique was examined and most errors were less than 50 g.     

Effect of intermittent feeding,structural components and phytase on performance and behaviour of broiler chickens

1. Two experiments were conducted to study the effect of intermittent feeding on performance and the efficacy of an exogenous phytase, and to assess whether intermittent feeding changed the activity pattern of broiler chickens.

2. Broiler chickens were given, either ad libitum or intermittently, a phosphorus deficient pelleted diet containing either coarsely or finely ground oat hulls and either no enzyme or a phytase added from 10 d of age, in a 2 × 2 × 2 factorial arrangement. Ad libitum feeding consisted of continuous access to feed in a room with 18 h of light and 6 h of complete darkness, whereas birds on intermittent feeding had restricted access to feed from 7 d of age, with 4 1-h feeding bouts/d and one 2-h feeding bout/d from d 14.

3. Performance, characteristics of the anterior digestive tract and phosphorus retention were assessed in experiment 1, while in experiment 2, birds were observed during 4-h periods to quantify different behaviours.

4. Intermittent feeding and phytase improved performance, but intermittent feeding did not improve the efficacy of the enzyme added. Ad libitum fed broiler chickens ate and drank on average twice per hour, and spent close to three-quarters of their time resting. Apart from an increased standing and feed searching activity for intermittently fed birds compared to ad libitum fed birds during the last hour before feed was presented, no differences in activity was detected.

5. It was concluded that broiler chickens quickly adapt to intermittent feeding without reduction in final body weight and with improvements in feed efficiency, but without improving the efficacy of dietary phytase. Only small changes occur in the behaviour of intermittently fed birds compared to ad libitum fed birds.     

The effects of restricted feeding on adrenal cortical activity in the immature domestic fowl

1. The effect of reducing food intake to 75% of the ad libitum intake was determined from hatching to 8 weeks in young Light Sussex chickens.

2. Restricted birds were lighter throughout the experiment.

3. Relative adrenal weight tended to be greater in restricted birds but the difference decreased with time.

4. There was no depletion of adrenal cholesterol: from week 5 there was a significantly greater amount in the adrenals of restricted birds.

5. After 1 week of restriction plasma corticosterone concentration was 73% greater than in controls. It decreased progressively, falling within the normal range at 5 weeks.

6. Restricted birds were hypoglycaemic from weeks 2 to 7 and hyper‐lipacidaemic throughout. A negative correlation between plasma glucose and free fatty acids was found.     

The relationship between plasma triglyceride concentrations and body fat content in male and female broilers—a basis for selection?

1. The relationship between plasma triglyceride concentrations and body fat content was examined in three groups of male and one of female broiler chickens fed ad libitum on a normal growing diet.

2. Phenotypic correlations between total plasma triglyceride concentration and fat content were + 0.50, + 0.37 and + 0.39 for the three groups of male broilers and +0.33 for the group of females. Triglyceride content of plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) showed similar correlations with fat content.

3. Selection of birds from a flock of 550 male broilers on the basis of high or low plasma VLDL plus LDL triglyceride concentrations produced groups with significant differences in body fat content but little difference in body weight.

4. The results suggest that measurements of plasma triglyceride concentration could be used as an indirect means of selecting for decreased body fat content in broiler breeding programmes.     

The occurrence of giant fibres in different muscles of two chicken genotypes

1. The occurrence of Giant Fibres (GF) in three muscles (Pectoralis major (PM), Iliotibialis lateralis and Semimembranosus) with different types of energy metabolism was studied in slow- and fast-growing chicken strains.

2. A total of 20 one-day-old Leghorn chicks (slow-growing) and 20 broiler (Ross 508) chicks (fast-growing) were reared to 100 and 45 d, respectively.

3. A small percentage of GF was seen in pre rigor muscle samples even at 3 min post mortem in both genotypes and in all muscle types studied.

4. From 3 min to 24 h post mortem GF increased both in Leghorn and broiler chickens but to a different extent according to muscle type and genotype.

5. The highest GF 24 h post mortem value was found in the PM muscles belonging to the fast-growing broiler line.

6. It was concluded that every type of muscle can develop GF, but this phenomenon is more evident in the PM especially in animals selected for increased growth rate.     

Efficacy of a Brazilian calcium montmorillonite against toxic effects of dietary aflatoxins on broilers reared to market weight

1. The protective effect of a natural Brazilian calcium montmorillonite (CaMont) against aflatoxins was studied in broiler chickens.

2. A total of 1056-d-old Cobb male broilers were housed in experimental pens (22 chickens per pen) for 42 d. Three levels of CaMont (0, 2.5 and 5 g/kg) and two levels of aflatoxins (0 and 3 mg/kg) were assayed. Each treatment had 8 replicate pens of 22 broiler chickens each.

3. Of all the chickens tested in the experiment, the ones treated with aflatoxins were the most adversely affected. CaMont treatment at concentrations of 2.5 and 5 g/kg improved body weight of chickens at 42 d of age by 13.3% and 22.7%, increased daily feed intake by 9.7% and 24.7%, and improved the productive efficiency index of chickens by 53% and 66.5%, respectively.

4. Dietary CaMont positively affected parameters such as weight of liver, heart and gizzard; however, serum potassium concentration decreased by 15.3% compared with that of chickens given only the aflatoxin-contaminated diet.

5. CaMont did not cause adverse effects in chickens that did not receive aflatoxins.

6. CaMont at pH 8.5 partially reduced the toxic effects of aflatoxins in broilers when included at levels of 2.5 and 5 g/kg in the diet.     

Lipopolysaccharide reduces food passage rate from the crop by a prostaglandin-independent mechanism in chickens

1. We examined the effect of lipopolysaccharide (LPS), a component of Gram-negative bacteria, on food passage in the digestive tract of chickens (Gallus gallus) in order to clarify whether bacterial infection affects food passage in birds.

2. Food passage in the crop was significantly reduced by intraperitoneal (IP) injection of LPS while it did not affect the number of defecations, suggesting that LPS may affect food passage only in the upper digestive tract.

3. Similar to LPS, prostaglandin E2 (PGE2), one of the mediators of LPS, also reduced crop-emptying rate in chickens while it had no effect on the number of defecations.

4. Pretreatment with indomethacin, which is an inhibitor of cyclooxygenase (COX), a prostaglandin synthase, had no effect on LPS-induced inhibition of crop emptying.

5. IP injection of LPS did not affect the mRNA expression of COX2 in the upper digestive tract of chickens.

6. It is therefore likely that LPS and PGE2 reduced food passage rate in the crop by a prostaglandin-independent pathway in chickens.     

Application of computed tomography to assess the effect of egg yolk ratio on body composition in chickens of different genotype and gender at hatch and during the rearing period

1. Computed tomography was used for the in vivo determination of yolk ratio in 7000 domestic hen eggs, originated from two markedly different genotypes, in order to examine the effect of egg yolk ratio, gender and genotype on the development of hatched chicks.

2. Eggs with extremely low, average and extremely high yolk ratio were chosen for further investigation (n = 350 in each group in both genotypes). After incubating the selected eggs, hatched birds were reared and slaughtered at 11 weeks of age.

3. The yolk ratio of eggs significantly affected the body composition of the chickens at hatching and during rearing to 8–9 weeks of age.

4. Chickens of a genotype selected partly for weight gain had significantly higher live weight from hatching to the end of the rearing period and had better slaughter characteristics than those of the dual purpose TETRA-H genotype.

5. At hatching, only the dry matter content of the body was affected by the gender of the birds. The effect of gender on the live weight and body composition of chickens was evident from the 5th week of age to the time of slaughter.

6. It was concluded that eggs with a low yolk ratio were most beneficial for broiler production, because chickens hatched from these eggs had the highest slaughter weight and muscle index and the lowest fat index for their body mass.     

Physical and chemical properties of meat from scavenging chickens and helmeted guinea fowls in response to age and sex

1. The effects of age and sex on body weight, carcass traits, physical and chemical properties of breast muscle from chickens and helmeted guinea fowls managed under village free-range conditions were assessed in random samples of 48 guinea fowls and 48 chickens obtained from local markets.

2. Guinea fowls had higher body weight, hot carcass weight, cold dressed weight and breast weight than chickens.

3. Guinea fowls had more dry matter, protein and less fat than chickens. Ash content did not differ between guinea fowls and chickens. Protein and fat increased, whereas dry matter and ash decreased with age (P < 0.05)

4. Chicken meat was lighter, less red and more yellow than guinea fowl meat. Cooking loss was higher in guinea fowls, male and grower birds than chickens, females and adult birds, respectively. Shear force was affected by age, as mature birds had a higher value than growers.

5. Guinea fowl carcasses contained more meat that was leaner, higher in protein and redder compared with chicken meat. As age increased the meat increased in protein and fat content and shear force, whereas colour became darker, redder and yellower.     

Ileal MUC2 gene expression and microbial population,but not growth performance and immune response,are influenced by in ovo injection of probiotics in broiler chickens

1. The objective of present study was to evaluate the effects of intra-amniotic injection of different probiotic strains (Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici) on the intestinal MUC2 gene expression, microbial population, growth performance and immune response in broiler chicken.

2. In a completely randomised design, different probiotic strains were injected into the amniotic fluid of the 480 live embryos (d 18 of incubation), with 4 treatments and 5 replicates. Ileal MUC2 gene expression, microbial profile, growth performance and immune response were determined.

3. Injection of probiotic strains, especially B. subtilis, had significant effect on expression of the MUC2 on d 21 of incubation and d 3 post-hatch, but not on d 19 of incubation.

4. Injection of the probiotic strains decreased significantly the Escherichia coli population and increased the lactic acid bacteria population during the first week post-hatch.

5. Inoculation of probiotics had no significant effect on antibody titres against Newcastle disease virus, antibody titres against sheep red blood cell and cell-mediated immune response of chickens compared to control.

6. In ovo injection of the probiotic strains had no significant effect on growth performance of broiler chickens.

7. It was concluded that injection of probiotic bacteria especially B. subtilis into the amniotic fluid has a beneficial effect on ileal MUC2 gene expression and bacteria population during the first week post-hatch, but has no effect on growth performance and immune response in broiler chickens.     

Effects of a blend of essential oils and overcrowding stress on the growth performance,meat quality and heat shock protein gene expression of broilers

Overcrowding stress is common in the poultry industry. Chickens exposed to long-term stressful situations are characterised by welfare impairment and immunosuppression.

1. The present study evaluated the effects of a blend of essential oils (EOB; cinnamaldehyde and thymol) and stocking density on the performance, gut microflora, meat quality and physiological stress markers of broilers.

2. One-day-old Ross 308 male broiler chickens (n = 360) were allocated to 4 experimental groups from d 22 to 42. Each treatment had 6 replicates of 15 chicks. Two groups were subjected to a high stocking density (HSD) of 20 birds/m² and the other two groups were kept at a low stocking density (LSD) of 10 birds/m².

3. The results of this study indicate that overcrowding stress decreased growth performance parameters, blood immunoglobulin (Ig)G and heterophil:lymphocyte (H:L) ratio but increased IgA and IgM levels. HSD reduced water-loss rate and pH decline at 45 min post mortem in the breast muscle.

4. Essential oils supplementation elevated H:L ratio but decreased breast meat redness and pH₂₄.

5. Significant interactions between EOB and stocking density were observed for corticosterone (CS) level and mRNA levels of heat shock protein 70 (HSP70) in brain and heart. Although HSD increased CS and HSP70 when compared to LSD, the effects of the former were inconsistent with EOB supplemented diets.

6. In conclusion, dietary EOB supplementation could improve some of the biomarkers associated with overcrowding stress in broiler chickens.     

Reduction of Salmonella typhimurium in laboratory-inoculated chickens by the use of erythrosine

1. The numbers of Salmonella typhimurium in the caeca of infected chickens were reduced in birds given the food colour erythrosine in their drinking water.

2. Numbers of selected groups of faecal bacteria were not reduced by erythrosine.

3. No effect could be detected in the organoleptic properties of chickens processed after treatment with erythrosine.     

Performance and digestive function of broiler chickens given grit in the diet

1. A series of experiments were carried out to study the effect of grit on broiler performance, gizzard development and fate of grit in the digestive tract.

2. In Experiment 1, performance, gizzard weight and content of grit in the gizzard of broiler chickens given access to granite-type grit was investigated. In Experiment 2, the effect of grit stones on performance and gizzard development was assessed in diets with or without whole wheat.

3. In Experiment 3, the effect of grit in the form of zeolite, granite or marble on gizzard development and digestive tract grinding and passage was studied in diets with or without whole wheat.

4. Grit stones had no effect on performance of broiler chickens, which may be explained by the fact that grit stones did not stimulate gizzard development to the same extent as with other structural materials.

5. The lack of stimulation is at least partly due to the fact that a majority of the grit stones eaten pass through the small intestine without being retained in the gizzard.

6. Grit in the form of marble reduced feed intake and weight gain.     

Natural resistance of Sri Lankan village chicken to Salmonella gallinarum infection

1. An experiment was conducted to compare the natural resistance of an indigenous breed of local village chickens to Salmonella gallinarum with two commercial breeds: ISA Brown and ISA White layers under experimental conditions.

2. A total of 72 chickens from each of these breeds were randomly distributed to 4 pens to provide equal numbers of two replicate pens maintained as infected and control (uninfected). All chickens in infected groups were inoculated orally with 1 × 10⁸ CFU (1 ml dose) of a field isolate of S. gallinarum, at the age of 8 and 16 weeks given over 5 consecutive days. Growth performance, clinical signs, gross pathological lesions and antibody responses were measured.

3. A significantly higher mortality was observed in the brown layers compared with the white layers, and clinical signs and mortality were absent in village chickens. However, a large number of birds with gross lesions and high antibody titres were detected in village chickens, indicating that birds had the disease subclinically. Commercial breeds had a significantly higher body weight, feed intake and feed conversion efficiency.

4. There was a significantly lower proportion of positive reactors in village chickens in the whole-blood agglutination test (35%) compared to brown (100%) and white (90%) layers even after the second inoculation. Uninfected birds were negative in all groups. The indirect enzyme-linked immunosorbent assay confirmed these observations.

5. These results suggest that the indigenous breed had superior natural resistance to S. gallinarum than the commercial breeds.     

Polymorphism and expression of insulin-like growth factor 1 (IGF1) gene and its association with growth traits in chicken

1. The objectives of the study were to detect polymorphism in the coding region of the IGF1 gene, explore the expression profile and estimate association with growth traits in indigenous and exotic chickens.

2. A total of 12 haplotypes were found in Cornish, control layer and Aseel breeds of chicken in which the h1 haplotype was most frequent.

3. Nucleotide substitutions among haplotypes were found at 21 positions in the IGF1 gene in which 4 substitutions resulted in non-synonymous mutations in the receptor binding domain of the IGF1 protein.

4. The haplogroup showed a significant effect on body weight at 24 and 42 d of age in the control layer line, body weight at 42 d and daily weight gain between 29 and 42 d in the control broiler line, daily weight gain between 29 and 42 d in Cornish, and body weights at 42 d as well as daily weight gain between 29 and 42 d in Aseel birds.

5. IGF1 expression varied among the breeds during embryonic and post-hatch periods. The expression among the haplogroups varied in different chicken tissues. The effect of haplogroup on myofibre number in pectoral muscle was non-significant, although there was significant variation in numbers between d 1 and d 42, and between broiler and layer lines.

6. It was concluded that the coding region of the IGF1 gene was polymorphic, expressed differentially during the pre-hatch and post-hatch periods, and haplogroups showed significant association with growth traits in chicken.     

Relationship between monensin and sulphur amino acid requirements IN broiler chickens

1. Diets containing 80, 100, 125, 150, 175 or 200 mg monensin/kg were fed to broiler chickens from 0 to 28 d in cages that prevented access to excreta.

2. Growth was depressed with 125 mg monensin or more/kg and food intake tended to decrease. Feathering was adversely affected with 175 mg or more/kg.

3. In a similar experiment, diets containing 8.8, 9.1, 9.4, 9.7 or 10.1 g total sulphur amino acids (SAA)/kg were supplemented with 125 or 80 mg monensin/kg and compared with a diet containing 8.8 g SAA and 33 mg robenidine/kg.

4. With 125 mg monensin/kg, body‐weight gain was significantly less than that of birds receiving robenidine if dietary SAA content was 9.4 g or less/kg. With 9.7 g SAA or more/kg, gain in birds receiving monensin was similar to that of birds receiving robenidine.

5. Monensin at 125 mg/kg therefore appears to increase the SAA requirement.     

Growth and food intake of intact and pinealectomised chickens treated with melatonin and triiodothyronine

1. Male chickens of an egg‐laying strain were used in an investigation of the effects of pinealectomy at 1 d after hatching.

2. Pinealectomised birds killed at 28 d of age were significantly heavier than sham‐operated chickens; intraperitoneal treatment of intact birds during the same period with 10 mg melatonin/kg d depressed weight gain, while 200 μg triiodothyronine (T₃)/kg d given intramuscularly had no effect.

3. Pinealectomized birds aged 11 weeks ate some food during the night, in contrast to intact birds, and ate significantly more food per 24 h; their short‐term food intake responded to melatonin and T₃ in a manner similar to that of intact birds.

4. The electroencephalogram (EEG) of pinealectomised birds was affected to a slight degree by darkness, while in intact chickens there is a rapid and marked change in the EEG.     

The occurrence of salmonellae during the rearing of broiler birds

1. The incidence of salmonellae was studied in two broiler houses at each of two commercial sites in an integrated commercial enterprise.

2. Salmonellae were not isolated from the empty, cleaned and fumigated houses and only on one occasion from the foodstuffs.

3. Salmonellae were isolated from the environment of the chicks and spasmodically from the litter, water troughs and dust.

4. The incidence of infection of the chicks did not influence the number of isolations of salmonellae from the environment of the birds during rearing.

5. Water in the water troughs rather than foodstuffs appeared to be the major oral route of infection or re‐infection of birds during rearing.