Cross‐contamination during the scalding and plucking of broilers

1. Experiments were carried out in two poultry slaughtering plants to estimate cross‐contamination occurring during the scalding and plucking of broilers.

2. To simulate the external (dust and feather) and internal (intestinal) contamination of broilers the carcasses were artificially contaminated with a strain of Escherichia coli K12.

3. Cross‐contamination occurred at both stages in the processing when the carcasses had been contaminated externally; when the broilers had been contaminated internally slight cross‐contamination occurred only during plucking.

4. Broilers which were contaminated externally before scalding resulted in more numerous carcasses that were contaminated after the whole slaughtering procedure than those contaminated internally.

5. In one processing plant there were fewer contaminated carcasses after cooling than after plucking, while in the other plant no differences were found in the number of positive carcasses after these two stages in processing.     

Comparison of DL‐methionine and methionine hydroxy analogue‐free acid in broilers by using multi‐exponential regression models

1. Methionine hydroxy analogue‐free acid (MHA‐FA) was evaluated for biopotency compared to DL‐methionine in a practical diet for broiler chicks.

2. Both methionine sources were added at equimolar concentrations of 0.03, 0.07, 0.11, 0.15, 0.20 and 0.25% to the diet.

3. A non‐linear multi‐exponential regression model was used to describe the weight gain and food conversion response to supplemental sources of methionine.

4. Compared with DL‐methionine on an equimolar basis, bioefficacy of MHA‐FA was calculated at 73% from weight gain and 68% from food conversion data, respectively. This corresponds to an efficiency of Alimet® between 60 and 64% relative to DL‐methionine on a weight for weight basis.     

Hydrogenated oil decreases tissue concentrations of n‐6 polyunsaturated fatty acids and may contribute to dyschondroplasia in broilers

1. In a factorial design of dietary treatments, male Ross broilers were given diets containing soyabean oil, hydrogenated soya‐bean oil (as a source of trans‐fatty acids) or feed fat with either 0 or 300 μg of added D‐biotin/kg.

2. Growth to 28 d was not influenced by the dietary treatments.

3. Length of tibiotarsal bones was reduced (P<0.05) and severity of leg bone cartilage lesions, characteristic of dyschondroplasia, was highest (P<0.05) in broilers fed on diets containing hydrogenated soyabean oil.

4. Feeding hydrogenated soyabean oil lowered (P< 0.05) the concentrations of C₂₀:_4n6 and the ratios of C_20:4n6/C_18:2n6 in liver and growth plate cartilage.

5. Growth plate cartilage from birds affected with dyschondroplasia contained lower proportions of prostaglandin precursor fatty acids compared with normal growth plate.

6. It is speculated that an inhibition of prostaglandin biosynthesis brought about by the presence of trans‐fatty acids might contribute to the occurrence of lesions similar to dyschondroplasia.     

Effect of early filleting on the texture of breast muscle of broilers stunned with argon‐induced anoxia

1. Eighty broilers were stunned in batches of 10 with less than 1 % oxygen (air displaced by argon) and their chilled breasts were filleted at 2, 3, 5 or 21 h (argon control) post‐mortem. Twenty broilers were electrically stunned and their breasts filleted at 21 h post‐mortem (electrical control).

2. Meat quality variables studied included pH of the pectoralis major muscle measured at 20 min post‐mortem and at filleting, and texture at 24 h post‐mortem.

3. Argon stunning resulted in a rapid early post‐mortem pH fall, but there was no indication of heat toughening in the breast muscles.

4. Filleting at 2 h post‐mortem, after argon stunning, resulted in 5% of the p. major muscles having greater than 4 kg yield force (slightly tough).

5. Although post‐mortem ageing of argon stunned broilers improved the texture of breast muscle, it is inferred that filleting at 2 h postmortem resulted in breast muscle with acceptable texture.     

Factors affecting the diet selection of choice‐fed broilers

1. In one experiment two strains of choice‐fed broilers were given wheat, either whole or ground, and a balancer diet, either pelleted or as a mash, for 4 weeks. They were compared with broilers given a complete single feed.

2. In a second experiment, the effect of a pelleted or mash balancer, relative feeding trough space for whole wheat and balancer (1:1 or 2:1 with total feeding space constant) and group size (20, 40 or 80 broilers maintained at a constant stocking density) on the diet selection of choice‐fed broilers was examined.

3. Food form had a large effect on diet selection although there was no effect on total food intakes or weight gains. If a mash balancer was provided, the broilers selected a greater proportion of wheat when it was ground rather than whole, but if the balancer was pelleted a greater proportion of wheat tended to be selected when whole wheat was provided.

4. No significant differences in diet selection were observed as a result of differences in the strain of broiler, the relative amounts of feeder space for wheat and balancer or group size.     

Apparent independence of glucose tolerance and body fat content in 8‐week‐old broilers

1. A possible relationship between glucose tolerance and body‐fat content was examined in broilers selected at 2 and 4 weeks of age for fast or slow glucose disposal.

2. At 8 weeks of age, selected chickens were different in glucose tolerance but similar in body weight, food conversion efficiency, carcass composition and glucose‐induced insulin release.

3. Therefore, variations in glucose regulation and insulin sensitivity which are detectable at an early age, do not appear to be related to body composition in 8‐week‐old broilers.     

Effect of β-glucosidase on the meat quality and digestibility in broilers

This study investigated the effects of supplementary β-glucosidase on the carcass composition, meat quality, weight of digestive organ and apparent digestibility in male broilers. Two hundred and forty male, 1-day avine broiler chicks were randomly allocated into four treatment groups and fed with corn-soya bean meal supplemented with 0 (control), 0.6, 1.2 and 1.8 U/g of β-glucosidase respectively. The results showed that there were no significant differences (p > 0.05) among groups in carcass composition (percentages of eviscerated yield, half-eviscerated yield, muscle yield of breast and leg). However, adding 0.6 U/g β-glucosidase to the diet not only altered the meat quality by decreasing the drip loss ratio (p < 0.05) and relative lightness (L*) value (p < 0.01), increasing relative redness (a*) value (p < 0.01), but also significantly decreased the pancreas to body weight ratio (p < 0.05), however, with little effect on liver, proventriculus and gizzard to body weight ratio (p > 0.05). The length and width of duodenum villus were not affected by the addition of β-glucosidase, but the coefficients of total tract apparent digestibility of protein and fat increased by 9.02% (p < 0.05) and 7.40% (p < 0.01) respectively; the parameters of ash were not affected by β-glucosidase addition (p < 0.05). This study provided valuable information for evaluation of the effect of supplementary β-glucosidase on the meat quality and digestibility of broilers.     

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.     

Contribution of rigor shortening and cold shortening to variability in the texture of Pectoralis major muscle from commercially‐processed broilers

1. Three experiments were conducted to establish the degree to which cold shortening and rigor shortening contribute to variability in the texture of Pectoralis major (PM) muscles of commercially processed broiler carcases chilled at different rates.

2. In the first experiment, free range and standard broiler carcases were air‐chilled under normal commercial conditions at 0°C. Strong negative correlations between pH values 15 min post‐mortem (pH_{15 min}) and sarcomere length indicated that some cold shortening had occurred, while evidence supporting the occurrence of rigor shortening was much weaker. Regardless of the cause of muscle shortening, weak negative correlations between shear force and sarcomere length indicated that shorter sarcomeres were associated with tougher meat. In addition, strong negative correlations between pH values 24 h post‐mortem (pH_{24 h}) and cooking losses suggested that increased juiciness is associated with higher ultimate pH values.

3. In the second experiment, carcases were either chilled rapidly in water at 0°C (23 h) or in water at 10°C (10 h or 23 h) to identify the individual contributions of cold and rigor shortening to textural variability more precisely. In carcases chilled rapidly in water at 0°C, textural variability was low and toughness was absent, suggesting an absence of both cold and rigor shortening. However, few of these carcases had pH_{15 min} values sufficently high (≥ 6.70) to promote a cold shortening effect. In contrast, carcases chilled in water at 10°C, which had a similar deep muscle cooling rate as air‐chilling at 0°C, showed evidence of rigor shortening, because they had a wider range of sarcomere lengths and higher shear force values than carcases chilled in water at 0°C.

4. In the final experiment, carcases were either chilled in air at – 12°C, a cooling rate similar to that of water‐chilling at 0°C, or chilled in air at 0°C. Cold shortening and increased toughness was evident with both chilling regimens in those carcases with pH_{15 min} values ≥ 6.70. In contrast, in carcases with pH_{15 min} values < 6.70, both chilling regimens reduced sarcomere shortening and improved tenderness. However, the mean shear value of the carcases chilled in air at – 12°C was almost 1.00 kg cm^–2 lower than diose chilled in air at 0°C.

5. In conclusion, both cold shortening and rigor shortening can occur during the commercial air‐chilling of broilers at 0°C and thereby contribute considerably to textural variability and incidences of toughness. Faster chilling, either in water at 0°C or in air at – 12°C, has been shown to eliminate the risk of adverse rigor shortening and toughness.     

Clinical signs of fatty liver and kidney syndrome in broilers and their alleviation by the short‐term use of biotin or animal tallow

1. Birds affected by fatty liver and kidney syndrome (FLKS) had elevated concentrations of serum Na⁺, K+, lactate, pyruvate and uric acid and reduced concentrations of serum HCO‐₃ and glucose.

2. Short‐term treatment with biotin or animal tallow reduced the mortality from FLKS and prevented the clinical signs.

3. Lactic acidosis may be a major factor contributing to the mortality and physical symptoms observed in birds affected by FLKS. The lactic acidosis and the hypoglycaemia observed in FLKS are due primarily to an accumulation of pyruvate as a result of an insufficiency of biotin for normal pyruvate carboxylase activity.     

Irradiation‐induced off‐odour in chicken and its possible control

1. Volatiles isolated from irradiated raw chicken were analysed by gas chromatography (GC) in conjunction with olfactory assessment of the effluent carrier gas to locate compounds with strong smells.

2. Sixteen odours of differing intensities were registered, some, but not others, coinciding with recognisable GC peaks. Identifications were made on the basis of retention data, mass spectrometric information and odour quality agreement.

3. Dimethyltrisulphide was found to be the most potent and obnoxious compound (foul gas, sulphurous), followed by cis‐3‐ and trans‐6‐nonenals (soapy), oct‐1‐en‐3‐one (mushroom) and bis(methylthio‐)methane (foul). With the exception of oct‐1‐en‐3‐one, none of these compounds has been reported before in irradiated raw chicken.

4. α‐Tocopherol and ascorbic acid induce stability in tissues in vivo and post mortem. Chickens were reared on diets supplemented with high concentrations (800 mg/kg food) of each of these vitamins. Yields of irradiation volatiles from the tissues of these birds were very much reduced, compared to yields from similar tissues from birds fed unsupplemented diets.

5. Concomitantly with the reduced yield of volatiles, less odour was associated with the samples when analysed by GC‐olfactory analysis.

6. The use of enhanced concentrations of the two vitamins in combination in the diet of poultry may provide a means of controlling development of off‐odour in irradiated raw chicken, thus improving acceptability to the consumer.     

Effects of endotoxin,interleukin‐1/3 and prostaglandin injections on fever response in broilers

1. The effect of endotoxin, interleukin‐1β and prostaglandin on fever response was studied in 80 broilers (Hubbard strain). Endotoxin (E. coli, LPS) was injected iv (1.5 μg/kg) and icv (1.5 μg/bird); interleukin‐1 (human recombinant IL‐1β, 80 pg/bird) and prostaglandin E₂ (5 μg/bird) were injected icv. Indomethacin (10 mg/kg, iv) pretreatment was also used before iv endotoxin injection.

2. The results showed that indomethacin was able to block the fever response induced by iv endotoxin injection, and IL‐1β and PGE₂ were both effective in producing fever when injected icv. These data suggest a prostaglandin‐mediated fever response by broilers, and also a strong evidence of the involvement of endogenous pyrogen (interleukin‐1) in fever response in birds.     

Evaluation of methanol‐grown bacteria and hydrocarbon‐grown yeast as sources of protein for poultry: Performance of broilers during the finishing period

1. Three trials were carried out with male broilers during the 5‐ to 8‐week period, for the evaluation of two types of single‐cell protein (SCP) in practical‐type broiler finisher diets. The SCP tested were: Pruteen, produced from methanol‐utilising bacteria, and a Lavera‐type yeast which utilises the normal paraffins of heavy gas oil.

2. The inclusion of 90 to 100 g of either type of SCP/kg of the diet caused a 2 to 3% reduction in weight gain, a 3 to 5% decrease in food consumption, and up to a 2% improvement in food utilisation. The reduced growth rate could be fully explained by the decrease in food intake, with essentially no effect on food : gain ratio.

3 In diets containing Pruteen, arginine was second limiting after the sulphur amino acids.

4 An odd‐numbered fatty acid (17 carbons, unsaturation unknown) of Pruteen was not found in the carcass lipids of broilers fed on a diet containing 120 g Pruteen/kg.     

Effect of a soluble polysaccharide (carboxy methyl cellulose) on the physico‐chemical conditions in the gastrointestinal tract of broilers

1. The effects of an indigestible soluble polysaccharide (carboxy methyl cellulose: CMC) on broiler performance (body weight gain, food and water intake) and on chyme characteristics (moisture content, viscosity, pH, osmolality and retention time) in broilers were studied.

2. In semi‐synthetic diets 0, 5.0 and 10.0 g/kg of cellulose was replaced by CMC on weight basis. These diets were fed to male broilers from 3 to 5 weeks of age.

3. When 10.0 g/kg CMC was included in the diet, food intake and body weight gain were reduced, compared to the 0, and 5.0 g/kg CMC diets. Food:gain ratio and water intake were increased at each CMC concentration. The significant quadratic response showed an increased response per 5.0 g/kg dietary CMC at the higher CMC concentration.

4. The viscosity in the supernatant of the chyme was linearly increased in all intestinal segments by CMC. A quadratic increase was observed in the crop. In the lower ileum, differences between the 5.0 and 10.0 g/kg CMC diets were not significant.

5. CMC increased the mean retention time of chromium in the duodenum and in the upper jejunum, and reduced the maximal rate of marker excretion. The transit time (first appearance of the marker in the excreta), however, was significantly reduced at the highest CMC concentration.

6. The osmolality of the intestinal fluid decreased less as the chyme moved from the duodenum into the lower ileum, with increasing concentrations of CMC.

7. The ileal pH was reduced linearly by the CMC content of the diet.

8. Based on a higher moisture content of the chyme in the CMC‐fed birds, and the higher jejunal and ileal osmolarities in those birds, it was concluded that the efficiency of both digestion and absorption was reduced by CMC inclusion in broiler diets.     

Comparative evaluation of therapeutic efficacy of sulfadiazine-trimethoprim,oxytetracycline, enrofloxacin and florfenicol on Staphylococcus aureus–induced arthritis in broilers

1. Staphylococcus aureus is an important human and veterinary pathogen that causes economic loss in the poultry industry. This study aimed to compare therapeutic efficacy of 4 commonly used antibiotics in poultry on S. aureus–induced arthritis in broilers.

2. Sixty broilers, 8 weeks of age, were assigned at random into 7 groups as follows: (1) negative control (n = 5); (2) vehicle control (n = 5); (3) sulfadiazine-trimethoprim, 250 ml/1000 l drinking water (n = 10); (4) oxytetracycline 20%, 1 mg/l drinking water (n = 10); (5) florfenicol 10%, 1/1000 v/v in drinking water (n = 10); (6) enrofloxacin 10%, 1/1000 v/v in drinking water (n = 10) and (7) positive control (n = 10).

3. Birds in group 2 were injected with 1 ml of sterile TSB medium into the right tibiotarsal joint on d 0 while other birds (except group 1) were challenged with 1 ml of 1.2 × 10¹⁰ CFU/ml suspension of S. aureus bacteria.

4. Antibiotic therapy was started from d 4 post challenge and continued for 5 d. At the end, birds were weighed and clinical severity of arthritis was determined. After blood collection, birds were slaughtered and tibiotarsal and hip joints were evaluated grossly. The content of inflammatory exudates of tibiotarsal joint and the degree of femoral head necrosis were recorded. Mucin clot test and histopathological evaluation were performed on right tibiotarsal joint. Serum interleukin 6 was also assayed.

5. Sulfadiazine-trimethoprim had higher therapeutic efficiency with regard to most of the assayed criteria, whereas none of the antibiotics significantly affected femoral head necrosis and body weight. These data will help clinicians to have better antibiotic choice in field conditions.

     

Plasma alpha 1‐acid glycoprotein concentration in broilers: Influence of age,sex and injection of escherichia coli lipopolysaccharide

1. The influence of age, sex and injection of Escherichia coli lipopolysaccharide (LPS) on the plasma concentration of alpha‐1 acid glycoprotein (AGP) was determined in broilers using the single radial immunodiffusion method.

2. Plasma AGP concentration increased in the 3 d after hatching, and then stabilised at 240 ± 33 μg/ml up to 14 d of age.

3. No sex‐related differences in plasma AGP concentration were observed up to 6 weeks of age.

4. A single injection of 900 μg LPS per chick resulted in a 5‐fold increase in AGP concentration compared with that in saline‐injected chicks. Multiple injections of LPS (200 μg/chick every 2d for 14d) caused only a 50% increase in AGP concentration.     

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.     

Cellular proliferation of bile ductules and gamma‐glutamyl transpeptidase in livers and sera of young cattle following a single infection with Fasciola hepatica

Summary

During the course of experimental single infection with Fasciola hepatica in calves, the origin of the increased concentration of gamma‐glutamyl transpeptidase (γ‐GT) found to be present in the serum during the biliary stage of the disease, was studied.

The enzyme originates from the liver after flukes have caused intermittent and selective cholestasis in the bile‐duct system. The enzyme which normally is present in the bile ducts can under these circumstances enter the surrounding interstitial tissues through broken‐up junctions of the bile drainage system or be added to these from proliferating bile‐ductule epithelium. The multiplication of bile‐ductule cells can be looked upon as a neogenesis of cholangioles, which becomes essential when newly formed perilobular connective tissues prevent restoration of the anatomical connections of the bile capillaries with the biliary tree. The connective tissue growth is induced by bile fluid. An initially regional perilobular fibrosis is eventually distributed diffusely through the liver by migration of flukes.

The continued and extending fibrosis is due to the constant recurrence of intermittent and selective cholestasis. The transient occlusions of branches of the bile ducts are very likely to be attributable to persistent cholangitis. The growth of connective tissues has a considerable effect on the gain in weight of the liver.     

Expression of PDGFR-β and Kit in canine anal sac apocrine gland adenocarcinoma using tissue immunohistochemistry

Canine anal sac apocrine gland adenocarcinoma (ASAGAC) is an uncommon but highly invasive and metastatic malignancy. Toceranib phosphate (Palladia) is a receptor tyrosine kinase (RTK) inhibitor that targets several members of the split kinase RTK family. These membrane receptors are important for cell cycling, apoptosis and angiogenesis, all of which can contribute to carcinogenesis. The objective of this study was to evaluate archived, paraffin-embedded canine ASAGAC and normal canine anal sacs for immunohistochemical detection of Kit and platelet-derived growth factor receptor beta (PDGFR-β). Two of 77 neoplasms (2.6%) expressed Kit. Fifteen of the neoplasms (19.5%) were positive for PDGFR-β expression. None of the normal canine anal sac epithelium expressed Kit or PDGFR-β. Because of these results, further investigation should be considered to determine the role of RTKs in the clinical course and treatment of canine ASAGAC.