Browsing by Subject "wooden breast"
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(2021)Poultry meat has become popular in human diet and to secure the growing demand of poultry meat, breeders have developed broilers with fast growth and high breast muscle yield. Because of this genetic selection modern broilers are suffering from various quality defects in their breast muscles, one of which is called WB myopathy. The aim of the thesis was to study whether exercise, WB status or age have effects on ultimate pH and glycolytic potential (sum of total glucose and lactic acid content, given as lactate) in M. pectoralis major of modern broilers chickens. A total of 154 post-rigor breast muscle samples of male broilers of hybrid Ross 308 were used in this study. Broilers were divided randomly into three groups (A-C). Group A birds were not subjected to any exercise during the experiment. Group B birds lived 25 days exactly like group A but after that the drinking water dispensers was elevated to a higher level. Group C birds had their drinking water dispensers elevated to a 5 cm higher level after three days, and it was risen stepwise to 25 cm during the study. Broilers were slaughtered randomly from different groups at 20, 30 or 41 days old. Group B results were disregarded due to technical problems. Initial and ultimate pH, total glucose, free and in glycogen, and lactic acid contents for glycolytic potential, were determined from the breast muscle samples. The results showed that there were no differences between groups A and C (p > 0.05). There were differences between normal and WB cases in ultimate pH (pHu; p = 0.000), total glucose content (p = 0.000), lactate content (p = 0.007) and glycolytic potential (p = 0.000), but the pH values 5 minutes after death showed no significance (pH5; p = 0.190). There were differences in pHu, total glucose and glycolytic potential (p = 0.000), and lactate (p = 0.007), between ages 20, 30 and 41 days old birds. As the severity of WB increased in the breast muscle, the pHu increased and total glucose, lactate content and glycolytic potential decreased. The correlations showed significant relationships between WB score and all the above variables (p < 0.000). The results of the current study show that exercise does not have an effect on the levels of carbohydrates in M. pectoralis major of modern broiler chickens, but WB status and increasing slaughter age result a decrease in glycolytic potential and increase in ultimate pH.
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(2020)Wooden breast is muscle myopathy occurring in broilers, myopathy forms hard and pale connective tissue areas in broiler breast muscles. When wooden breast is occurring also some other myopathies can coexist: loose muscle structure and white stripping are visible on breast muscles. The myopathy is relatively new and it was noticed approximately ten years ago in greater amounts. The subject of this thesis was to study wing flapping and how it affects the morphology of breast muscles and bones and whether there are links between them and wooden breast prevalence. The literature review handled muscle morphology and bones morphology and how muscles shape changes when they grow in size, how muscles and bones grow normally and how the exercise of the muscles will affect wooden breast prevalence. In the literature review the anatomy of broiler movement and especially the anatomy of bones and the muscles that are involved in wing movement is handled. The study is made by raising 171 broiler birds divided in three groups: Group A birds have feed and water on floor level and birds do not have to use their wings. Group B birds lived same way as A-group until at day 25 drinking water is moved to platform which is higher than the floor level. Birds had to fly to platform and down when they need water or feed. Group C feed and water were on floor level but after 3 days water was risen on the platform and platform was risen gradually when birds grew and all birds of the Group C learned how to get to platform. From the original 171 birds 17 were sacrificed outside the study due health reasons. The birds (171-17 i.e. 154) were terminated 20, 30 or 41 days old in 40, 58 or 56 bird batches. The percentage of termination was roughly equal in each group on each termination, except at Day 20, when Group A and Group B had had the same treatment, and there were no terminations in Group B. The aim of this thesis was to study effects of wing flapping to broilers morphological changes. This thesis showed that there were no significant differences in Group A and Group C between studied properties. Wing flapping showed no significant differences during sample termination days in morphological properties.
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(2021)Due to the significant increase in broiler growth rate and meat yield in poultry farming, a particularly urgent problem of muscle defects named Wooden Breast (WB) has appeared in chicken breasts. WB is pale in overall color due to muscle degeneration and exhibits varying degrees of hard touch. The appearance of chicken breasts with more severe WB may have blood oozing. Citrate synthase is a rate-limiting enzyme involved in the tricarboxylic acid cycle-oxidative phosphorylation. It catalyzes the formation of the product citric acid for the subsequent tricarboxylic acid cycle or is transported to the cytoplasm for protein and fatty acid metabolism. Its activity can regulate the organism's material and energy metabolism, and the activity of citrate synthase can be affected by nerve stimulation, hormone secretion, and exercise. This study is part of the Wing Flapping Project. This project aims to study the possible effect of exercise on WB to improve this syndrome. The 154 broiler chicken was randomly divided into three groups. ( A: control group with no exercise; B: exercise from 25d on and C: exercise from 3 d on). The water and feed would be set on different elevations to motivate the birds to do the wing flapping. There would be three slaughter date: d20, d30, d41. The samples would be taken from the middle area of the chicken breasts. The aim of this study is to analyze the activity of citrate synthase in mitochondria in chicken breast to study whether the difference in exercise conditions is the cause of WB formation in broilers and the effect of growth time on it. The results showed that wing- flapping exercise has no significant influence in wooden breast myopathy. The citrate synthase activity in severe wooden breast is significantly lower than the normal breast (p<0.05) and it decreased with the increasing severe degree of wooden breast.
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(2013)The literature review dealt with the principles and methods for the evaluation of the quality of raw meat and meat product in different aspects. The factors influencing the quality of meat products were also involved. A new type of muscular dystrophy in broiler Musculus pectoralis, wooden breast, has been found in broilers. The dystrophy results in fibrinogenesis and thus local hardening in the muscle, but poses no health risk in human consumption. The aim of the study was to explore the maximal percentage of wooden breast that can be used in the meat products without causing a perceived quality defect. In the preliminary tests, wooden breast was incorporated with normal meat in different percentages to make sausage and chicken nuggets. Different methods of comminuting were also applied in the processing of wooden breast. The quality of the products was evaluated through the measuring in different aspects. Comparison was made between normal products and products containing wooden breast, so that a maximal addition percentage of wooden breast was obtained. The results of the preliminary test were later verified in the pilot plant. The addition of wooden breast increased the shear force and binding strength of the sausage and finely chopped chicken nuggets but resulted little change on the shear force and binding strength of the ground chicken nuggets. The pH, redness, and yellowness of all types of products declined with the wooden breast treatment. Lightness of the products was increased by wooden breast. Through the verification in the pilot plant, sausage and two types of chicken nuggets allow the addition of wooden breast to replace at least 15% and 30% of the lean meat in the recipe, respectively. Due to the low incidence of the dystrophy, that high additions will not be necessary in the practice.
Now showing items 1-4 of 4