Kaempferol improves carcase characteristics in broiler chickens by regulating ANGPTL3 gene expression

1. The objective of this study was to examine the beneficial effects of kaempferol, a naturally occurring polyphenol, on carcase characteristics in broiler chickens and the mechanisms involved in this regulation.

2. Broiler chickens were randomly divided into 7 groups: control, carrier control, kaempferol (0·3%), kaempferol (0·6%), hypercholesterolemic (HLD), HLD and kaempferol (0·3%), HLD and kaempferol (0·6%).

3. Seven weeks after treatment, carcase characteristics, lipid levels in the blood and liver, expression of hepatic Angiopoietin-like protein 3 (ANGPTL3) mRNA, and expression of adipose lipoprotein lipase (LPL) protein were determined.

4. Treatment with kaempferol (0·3 or 0·6%) significantly increased plasma high-density lipoprotein cholesterol levels, decreased percentage of abdominal fat, thickness of subcutaneous fat, plasma and hepatic total cholesterol and triglyceride concentrations, muscle malondialdehyde level and down-regulated expression of ANGPTL3 mRNA concomitantly with up-regulated expression of LPL protein in normal and hypercholesterolemic broiler chickens.

5. Kaempferol (0·3 or 0·6%) treatment had no significant effect on the values of percentage of breast muscle, percentage of leg muscle, carcase weight and eviscerated percentage.

6. The results suggest that kaempferol improves carcase characteristics by decreasing expression of ANGPTL3 in broiler chickens.     

Protective effect of ubiquinone (coenzyme Q9) on ascites in broiler chickens

1. The effect of ubiquinone (C0Q9) on ascites in broiler chickens was investigated.

2. The commercial broilers were divided into 2 groups of 100 birds each; CoQ9‐treated group and non‐treated group.

3. The chickens were grown in a positive‐pressured house with double high efficiency particulate air filtered intakes and exhaust, and thus were strictly isolated from infectious agents.

4. The chickens (15 to 21 d old) were exposed to cold stress in order to induce ascites.

5. The number of birds with ascites in the C0Q3‐treated group was significantly lower than in the non‐treated group.

6. Survival and production rates were better in the CoQ^‐treated group than in the non‐treated group.     

Effects of dietary polysavone (Alfalfa extract) and chlortetracycline supplementation on antioxidation and meat quality in broiler chickens

1. A total of 360 1-d-old male commercial Arbor Acre broiler chickens were randomly assigned to 5 groups (6 replicates of 12 birds each) to evaluate the dietary effects of polysavone (0·5, 1·0 and 1·5?g/kg), a natural extract from alfalfa, and 0·15?g/kg chlortetracycline (CTC) on growth performance, antioxidation and meat quality of broiler chickens.

2. Over the 6-week study, feed intake increased significantly with CTC supplementation and final body weight (BW) was significantly higher for 1·0?g/kg polysavone and 0·15?g/kg CTC treatments. Feed:gain ratio was not significantly affected by the dietary treatments.

3. At 3 weeks of age, serum total superoxide dismutase (T-SOD) activity for all polysavone treatments was significantly higher than controls, liver T-SOD activity in 1·5?g/kg polysavone group was significantly higher than the control and CTC groups, and serum glutathione peroxidase (GSHPx) activity for 1·5?g/kg polysavone and liver GSHPx activity in all polysavone groups were significantly higher than CTC.

4. At 6 weeks of age, serum and liver T-SOD activity in 1·5?g/kg polysavone group and liver GSHPx activity for all polysavone treatments were higher significantly than the control and CTC groups, and serum malondialdehyde (MDA) content for all polysavone treatments was significantly lower than CTC.

5. Breast muscle T-SOD activity and pH value at 6 weeks of age were significantly higher and MDA content was significantly lower in 1·0 and 1·5?g/kg polysavone groups than in the control and CTC groups. Breast muscle shear force was significantly lower in l·5?g/kg polysavone group compared with the control, and drip loss for all polysavone treatments was significantly lower than CTC.

6. It was indicated that polysavone modulates antioxidation and modifies meat quality, but with no adverse effect on performance of broiler chickens, and that CTC can be beneficial to performance but has no beneficial effect on antioxidant function or meat quality.     

Effect of dietary energy restriction on retention of protein,fat and energy in broiler chickens

1. Broiler chickens were fed 60–100% of recommended energy intakes to study the effects of energy restriction on protein and fat retention.

2. At an energy retention of 179 kJ/kg W ^0·75 d, only protein was retained. At higher energy intakes, each increment in retention had a rather constant composition: about 85% energy in fat and 15% in protein. At lower energy intakes body fat was mobilised whereas protein was deposited.

3. The efficiencies of energy retention in protein and fat were estimated to be 0·66 and 0·86 respectively.

4. The rather constant composition of additional retained energy after additional energy supply provides an explanation for a linear relationship between energy intake and energy retention.     

Xylanase in broiler diets with differences in characteristics and content of wheat

1. Experiments were conducted to measure the effect of xy‐lanase supplementation on the performance of broilers fed on wheat‐based diets containing high and low extract viscosity wheat (experiment 1), baking and feeding quality wheat (experiment 2) and with variation in wheat content (experiment 3).

2. Xylanase supplementation improved food conversion ratios by 2·2–2·9% and body weight gain by 0·2–2·5%. This was independent of wheat characteristics but slightly dependent on the wheat content of the diet. These effects were related to a lowering of digesta viscosity.

3. Differences in extract viscosity of wheat were not reflected in broiler digesta viscosity.

4. Reduction of digesta viscosity resulted in only a slight improvement of litter score. Reduced intestinal viscosity decreased relative pancreas weight and to a lesser extent relative small intestinal weight.

5. Baking quality wheat Baldus gave better performance than the feed quality wheats Apollo and Slejpner.

6. It was concluded that xylanase supplementation of wheat‐based diets invariably had a positive effect on broiler performance.     

Factors influencing bacterial eggshell contamination in conventional cages,furnished cages and free-range systems for laying hens under commercial conditions

1.?The aim was to assess eggshell contamination in various laying hen-housing systems and to identify factors influencing this contamination.

2.?Fifty-eight laying hen farms in France were studied, including 21 flocks housed in conventional cages, 7 in furnished cages and 30 kept on-floor.

3.?Sixty eggs per flock were analysed to obtain counts of the total mesophilic flora. Data on equipment and hen management were collected.

4.?Mean bacterial count on eggshells tended to be higher in on-floor systems (4·82 ± 0·51 log CFU/eggshell) than in cage systems (4·57 ± 0·58 log CFU/eggshell, P = 0·09).

5.?Contamination increased with age of the hens, airborne dust concentration, manual packing of the eggs, and packing in plastic rather than in recycled-pulp egg-flats.

6.?The effect of the housing system on eggshell contamination, previously described in experimental assays, was confirmed under production conditions.     

Are genetically lean broilers more resistant to hot climate?

1. Genetically lean (LL) or fat (FL) male chickens were exposed to either high (32°C) or control (22°C) ambient temperature up to 9 weeks of age. They were fed on one of two isoenergetic diets differing in protein content: 190 or 230 g/kg.

2. At 22°C, weight gain of LL broilers was the same as in FL chickens, but at the high temperature LL birds grew to a greater weight than FL ones.

3. Food conversion efficiency was not affected by ambient temperature in LL chickens but was depressed in FL ones at 32°C.

4. Increasing dietary protein content did not alleviate heat‐induced growth depression irrespective of the genotype.

5. Gross protein efficiency was higher in LL chickens and was less depressed at 32°C than in FL birds.

6. Fat deposition decreased with increasing protein concentration at normal temperature in both genotypes; at high temperature, high protein content enhanced fatness, particularly in LL chickens.

7. Thus, genetically lean broilers demonstrated a greater resistance to hot conditions: this was indicated by enhanced weight gain and improved food and protein conversion efficiencies.     

Comparative development of digestive organs,intestinal disaccharidases and some blood metabolites in broiler and layer‐type chicks after hatching

1. Body weight, digestive organ weights, and activities of disaccharidases (maltase and saccharase) activities were determined from day of hatch to 21 d of age in meat‐ and egg‐type chickens. Blood plasma was analysed for enzyme activities and metabolite concentration.

2. In meat‐type chickens food intake and growth rate were about 3‐fold those in egg‐type chickens. Food efficiency was superior in meat‐type chickens throughout the experimental period.

3. Meat‐type chickens hatched with disaccharidase activities exceeding those found in their egg‐type counterparts 2‐ to 5‐fold. From 7 d of age on, this trend reversed, i.e. activity was much higher in egg‐type than in meat‐type chickens.

4. Blood plasma amylase activity increased gradually in meat‐type chickens and was higher than in egg‐type chickens to 14 d of age. No breed differences were observed for alkaline phosphatase or lactate dehydrogenase activities during the experimental period.

5. Blood plasma concentrations of total protein, albumin, glucose, and calcium, were lower in meat than in egg‐type chickens.     

Changes in eggshell conductance,water loss and hatchability of layer hens with flock age and moulting

1.?Changes in water loss, eggshell conductance and hatchability with flock age were monitored in layer hens in a commercial hatchery.

2.?Optimal water loss for maximal hatchability of layer eggs was found to be 12 to 13% of initial egg mass at d 18 of incubation.

3.?Mass specific water vapour conductance (GH₂Osp) increased linearly with flock age from 0·31 mg/(d·g·Torr) at the beginning of the first breeding season to 0·40 mg/(d·g·Torr) at its end after 77 weeks (=4·21 and 5·44 mg/(d·100 g·kPa), respectively).

4.?After forced moulting GH₂Osp increased from 0·35 to 0·41 mg/(d·g·Torr) (=4·76 and 5·58 mg/(d·100 g·kPa), respectively).

5.?The coefficients of variation of GH₂Osp increased with flock age from 14% at the beginning of the breeding season to 31% at the end of the second breeding season.

6.?In order to preserve normal incubation water loss for maximising hatchability, the humidity setting of an incubator should increase gradually, with flock age, from 53% RH to 66% RH in the first laying season and from 61% RH to 67% RH after forced moulting.

7.?A 3·5-fold increase (from 2 to 7%) in the difference between mean and median GH₂Osp of egg batches with flock age was found, indicating increasing frequency of microscopic cracks in eggshells with flock age. This has to be taken into account when setting the humidity regime in the incubator.     

Response of three class‐IV major histocompatability complex haplotypes to Eimeria acervulina in meat‐type chickens

1. The importance of MHC genes and background genes in controlling disease resistance, including resistance to avian coccidiosis, has not been clarified in meat‐type chickens.

2. The role of class IV MHC genes in resistance to Eimeria acervulina was assessed in F2 progeny of a cross between 2 meat‐type lines, selected divergently for immune response to Escherichia coli.

3. Disease susceptibility was assessed by lesion score, body weight, packed cell volume and carotene absorption.

4. Chickens with the “K” class IV MHC haplotype had lower lesion scores than chickens with “F” and “A” haplotypes.

5. Plasma carotene concentrations were higher in chickens with “K” haplotype and lower in chickens with “F” and “A” haplotypes whereas body weight and packed cell volume were less sensitive measures of Eimeria infection.

6. Eimeria acervulina resistance appears to be associated with MHC class IV genes; information about MHC haplotypes may be useful in selecting for increased resistance of meat‐type chickens to coccidiosis.     

Microbiological changes in the uneviscerated bird hung at 10 degrees C with particular reference to the pheasant

Thirty pheasants which had been reared in captivity for 19 weeks were killed by dislocating the neck and hung for up to 15 d at 10 °C. Microbiological, sensory and chemical assessments were made at 0, 3, 6, 8, 10, 13 and 13 d and this paper reports the microbiological results.

Examination of the duodenum, small intestine and caecum showed very little multiplication of coli‐aerogenes bacteria during hanging, although there was some increase in the numbers of faecal streptococci. Psychrophilic clostridia, mainly Clostridium putrefaciens, were found in the small intestine after 8 d and these organisms increased in number up to the 15th d.

The muscle remained relatively free from bacteria for most of the hanging period, but at 15 d Cl. putrefaciens was found in two out of three muscle samples at io³ and io⁴ per g.

No signs of spoilage due to greening were observed.

Twelve 16½>‐week‐old chickens were also killed by dislocating the neck and hung without plucking for 12 d at 10 °C with the pheasants. Although initially there were no major differences between the intestinal flora of the chickens and pheasants, faecal streptococci and coli‐aerogenes bacteria multiplied rapidly in the small intestine of the chickens during the first week. Greening occurred around the vent within 5 d.

Reasons for the differences between the two types of bird are discussed, particularly in relation to the diet.     

A comparison of the energy and nitrogen metabolism of fed ducklings and chickens

1. Energy measurements were made over 4 d on groups of three ducklings (aged from 5 to 22 d), and three broiler chickens (aged from 11 to 32 d) offered high‐ or low‐energy diets.

2. Food, metabolisable energy (ME) and water intakes were significantly higher for ducklings than for chickens. The ratio of water : food was 4.2 : 1 and 2.3 : 1 for ducklings and chickens, respectively. The food conversion ratio differed between diets but not species. Performance was generally better for both species on the high‐energy diet.

3. Heat production, energy, fat and protein retentions were higher for ducklings than chickens, and ducklings retained 0.44 of their energy as fat compared with 0.37 for chickens. Overall the ratio of protein (g) to fat (g) retention was 2.2 : 1 and 2.8 : 1 for ducklings and chickens respectively.

4. For ducklings, metabolisability of the high‐energy diet declined from 0.774 to 0.747, and to a lesser extent of the low‐energy diet, as they aged. There was no such decline for chickens. Net efficiency of utilisation of ME for gain was 0.64 for ducklings compared with 0.50 for chickens.

5. Fractional retention of dietary nitrogen (N) was 0.62 for ducklings and 0.55 for chickens. Gaseous ammonia‐N was 4.5 and 2.2%, respectively, of N retained.

6. In a second experiment groups of ducklings only, were offered high‐and low‐protein diets from 12 to 22 d of age. Comparisons among four diets showed that food and energy intake was lower on the low‐protein diet than on the other three. Energy retention on the high‐energy diet was greater (P<0.05) than on the other three diets.

7. It was concluded that a high‐energy diet is important for ducklings and chickens for maximum biological performance during the first 4 weeks of life.     

Comparative growth and development of the digestive organs and of some enzymes in broiler and egg type chicks after hatching

1. Body weight, the weight of digestive organs and activities of some digestive enzymes were determined from hatching to 14 d of age in meat‐ and egg‐type chickens.

2. Relative daily food intake and growth rate were much higher in meat‐than in egg‐type chickens. Relative daily food intake peaked at 30% of body weight at 3 d of age in meat‐type, and at 20% of body weight at 6 d of age in egg‐type chickens and then decreased gradually. The corresponding values for growth rate were 20 and 14%.

3. Allometric growth of the small intestine, intestinal contents and liver was greater in meat‐type chickens, but the growth of the pancreas attained a higher value in the egg‐type birds. Diminution of the vitelline residue was similar in the two breeds.

4. Pancreatic digestive enzyme activities were similar between stocks, but activities in the small intestinal contents were lower in meat‐type chickens.

5. The secretion of digestive enzymes in the newly‐hatched meat‐type chicken could be a limiting factor in digestion and, consequently, in food intake and growth.     

Effects of reduced dietary calcium and phytase supplementation on calcium and phosphorus utilisation in broilers with modified mineral status

1.?The impact of modified mineral status and dietary Ca:P ratio on Ca and P utilisation was measured in chicks with or without phytase supplementation.

2.?In a preliminary study, 4 diets were given to chicks from 3 to 15 d of age: D1 (6·5 g P/kg and Ca:P = 1·5) and D2, D3 and D4 (6·0, 5·4 and 5·0 g P/kg, respectively, and Ca:P = 1·2). Growth performance was similar across diets. Tibia ash was similar in chicks given D1 and D2, but was gradually depressed from D2 to D4 (?22%).

3.?In the depletion period, two groups of chicks, with similar performance, but with different mineral status were achieved by feeding them, from 5 to 15 d of age, diets with a similar Ca:P ratio of 1·2, but containing 6·3 or 5·2 g P/kg.

4.?During the subsequent 11 d of the repletion period, chicks from each of the two previous groups were given one of the 4 diets containing 5·7 g P/kg, but differing in their Ca (8·3 and 5·3 g Ca/kg) and microbial phytase (0 or 1000 FTU, Natuphos®) levels in a 2 × 2 × 2 factorial arrangement.

5.?At the end of the repletion period, the initially depleted chicks could not be differentiated from the non-depleted chicks, indicating the capacity of chicks to compensate for their initial depleted mineral status.

6.?Interaction between dietary Ca and phytase levels was not significant. Phytase improved growth performance and bone characteristics. Reduced dietary Ca enhanced feed intake and growth rate, but depressed bone dry matter and ash weight.

7.?At the end, diets supplemented with phytase maximised bone ash weight when chicks were fed with a Ca:P ratio of 1·5 but elicited the highest growth rate when chicks were fed with a Ca:P ratio of 0·9.     

Automatic weight separation of broiler chickens

1. The individual weight gains of 371 broiler chickens in a commercial flock were monitored to establish individual growth patterns.

2. The relationship between early and final body weight was investigated for individual chickens.

3. The feasibility of automatic separation of birds into different weight groups was evaluated and consideration given as to whether this technique could be used for sex‐separation of an as‐hatched flock.

4. The results suggest that the present commercial practice of male selection at flock depopulation may be less reliable than many producers believe.     

Nutritive value of triticale fed to cockerels and chicks

1. The chemical composition, and amino acid and starch bioavailabilities of 18 triticale varieties were studied. In addition, the water soluble pentosan (WSP) content of 8 varieties was determined.

2. A wide variation in protein (149 to 203 g/kg DM), starch (563 to 629 g/kg DM) and WSP (27·7 to 50·9 g/kg DM) was found between varieties.

3. The TMEn reproductibility was assessed in two laboratories, using Leghorn cockerels, Isabrown cockerels and 3‐week‐old chicks. There were no sismificant differences in the TMEn values (range 14·0 to 15·2 MJ/kg DM) between the two types of cockerel. The TMEn values of the varieties were similar for chicks (range 13·6 to 14·9 MJ/kg DM) and for cockerels, with the exception of one variety.

4. The bioavailability of starch (range 96·5 to 99·4%) of some varieties was higher for cockerels than for chicks. The mean bioavailability of amino acids for cockerels was 94·5%.

5. TMEn prediction equations were derived from the chemical composition of the varieties. Best‐fit equations were obtained for starch (R ² = 0·62, RSD = 0·24), ash (R ² = 0·58, RSD = 0·25) and WSP (R ² = 0·52, RSD = 0·27).     

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.     

Effect of age of donor on the responsiveness of dispersed and cultured chicken anterior pituitary cells to GnRH‐I

1. The aim of this study was to devise a method to prepare and culture anterior pituitary cells from juvenile and adult chickens in order to investigate mechanisms controlling gonadotrophin‐releasing hormone‐I (GnRH‐I) ‐induced luteinising hormone (LH) release in vitro.

2. The optimum culture medium for maintaining gonadotroph responsiveness to GnRH‐I was bicarbonate‐buffered and phenol red‐free Medium 199 supplemented with 10% foetal calf serum.

3. Cultured pituitary cells from juvenile chickens were more responsive to GnRH‐I than cells from adult cockerels, while no LH was released in response to GnRH‐I from pituitary cells from laying hens.

4. Cultured pituitary cells from adult chickens of both sexes released LH in response to 12‐O‐tetradecanoyl‐13‐phorbol acetate (TPA), an activator of an enzyme involved in intracellular signalling, protein kinase C.

5. It is concluded that freshly‐dispersed and cultured gonadotrophs from adult chickens do not regain their responsiveness to GnRH‐I as well as freshly‐dispersed and cultured gonadotrophs from juvenile chickens. It appears that the stimulus‐secretion coupling pathway between the GnRH‐receptor and the activation of protein kinase C in gonadotrophs from adult chickens is more easily disrupted by dispersion and culture than in gonadotrophs from juvenile chickens.     

The effect of glycerol inclusion on broiler performance and nutrient digestibility

1. Crude glycerol from biodiesel production was offered ad libitum to broiler chickens in a 21-d feeding and digestibility trial. The study was designed as a 3*2?+?1 factorial design with 3 concentrations (33, 67, 100?g/kg) of glycerol from 2 sources, A and B (PRS Environmental Ltd and John Thompson and Sons Ltd) and a control diet. The diets were formulated to contain apparent metabolisable energy (AME) of 12·95?MJ/kg (assuming 14·6?MJ/kg for glycerol).

2. No significant interactions occurred, so only the main effects were discussed. At 7–14?d, feed conversion ratio (FCR) showed a significant linear response with increased glycerol inclusion. However quadratic responses on FCR were observed for the 21–28?d period and 7–28?d.

3. Glycerol digestibility was significantly greater with birds offered the 67?g/kg and 100?g/kg glycerol-based diets in contrast to the digestibility of 33?g/kg glycerol-based diets.

4. Glycerol inclusion level also had an effect on AME, which increased linearly with increasing glycerol inclusion. Birds offered the diets containing glycerol also required less energy per unit gain in contrast to birds offered the control diet.

5. When examining the effect of source of glycerol, source A glycerol resulted in the highest AME (15·20 vs. 14·72?MJ/kg). There was no significant effect of glycerol source on the other performance parameters.

6. Glycerol digestibility was significantly greater with glycerol from source B (John Thompson and Sons, Ltd) with a mean value of 0·848 in contrast to source A (PRS Environmental), which had a somewhat lower mean glycerol digestibility of 0·757.

7. In conclusion, glycerol source did not affect performance and increasing level of glycerol improved FCR, with 67?g/kg inclusion resulting in the most efficient conversion of feed to gain without any negative effects upon nutrient digestibility.     

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.