不同季節、畜舍、性別和週齡對黑羽土雞之生長發育、屠體性狀和脂肪酸組成之影響

Effect of Different Season, Housing, Sex and Age on the Growth Development, Carcass Characteristics, and Fatty Acids Composition of Black Native Chickens

鍾怡君(Yi Chun Chung)

指導教授 ： 夏良宙

國立屏東科技大學/農學院/畜產系所/碩士(2008年)

https://doi.org/10.6346/NPUST.2008.00072

摘要

本研究之目的在探討不同飼養季節、畜舍和週齡對黑羽土雞各部位生長發育狀況及屠體中脂肪酸組成之影響，以期更加的瞭解黑羽土雞各部位從小到大之生長發育狀況，以及其胸肉、腿肉和腹脂中從小到大之脂肪酸組成的變化。試驗一為不同季節、畜舍和週齡對中型黑羽土雞生長發育、屠體性狀和脂肪酸組成之研究。本試驗主要分成冬季和夏季飼養商業用中型黑羽土雞。冬季和夏季皆各飼養4000隻雞，且平均分配至兩棟畜舍(水簾式畜舍及開放式畜舍)，每棟2000隻雞，公母各半，且採用公母分飼之方式。試驗期間，飼料及水採任食任飲之方式。每畜舍及性別處理逢機挑選100隻雞供試驗用，套上腳標並於每週秤重作為體重資料之來源直至12週齡試驗結束為止。自4週齡開始至12週齡試驗結束為止，每週每棟畜舍之公母雞各犧牲3隻進行屠體分切，以測定屠體各部位生長情形、肌肉剪力和保水性、骨骼強度及脂肪酸組成。試驗二為不同畜舍和週齡對大型黑羽土雞生長發育、屠體性狀和脂肪酸組成之研究。本試驗採商業用大型黑羽土雞4000隻，其試驗處理及試驗期間之飼養流程同試驗一。試驗期間為雞隻孵化後飼養至13週齡試驗結束為止。自4週齡開始至13週齡試驗結束為止，其屠體各部位生長情形、肌肉剪力和保水性、骨骼強度及脂肪酸組成之測定，皆同試驗一。

試驗一結果顯示，中型黑羽土雞無論是飼養在不同季節、畜舍以及不同性別之間，雖然其體重的部分以冬季飼養之雞隻明顯較夏季重，且公雞較重於母雞，但是其相對增重方面則皆是無差異的，並且皆在雞隻飼養至11週齡時，其相對增重皆會降至10%以下，因此雞隻飼養至11週齡以後再繼續飼養下去，其生長效率會非常差，為了減少成本浪費，建議雞隻飼養至11週齡時即可上市。各部位生長發育方面，以內臟器官的發育為最早，接著是骨骼的生長，然後是肌肉的生長，最後則是脂肪的蓄積。生殖器官方面，以睪丸販賣之重量觀點來看，建議中型黑羽土雞之公雞可在11至12週齡上市；而以母雞之卵巢發育來看，建議中型黑羽土雞之母雞在性成熟(12週齡)以前上市。肌肉強度方面，中型黑羽土雞飼養至11週齡以後，其肌肉強度幾乎不會再變得更強，因此建議雞隻可在11週齡時上市；且脂肪產量較高較為肥胖之雞隻，會使其肌肉強韌度減低。肌肉保水性方面，中型黑羽土雞之飼養全期，其肌肉保水性隨著週齡的增加並無明顯之變化。骨骼強度方面，隨著週齡的增加其脛骨長度及脛骨強度皆會隨之增加；且生長較快速體重較重之雞隻，會使其脛骨強度變差。脂肪酸方面，雞隻飼養在較低溫的環境下(冬季和水簾式畜舍)，其腿肉中之C16:0及C18:1的含量會增加；雞隻飼養在冬季會使其脂肪組織中的C18:2含量增加；公雞屠體中的必需脂肪酸含量高於母雞；而雞隻屠體中之C18:2含量會隨著週齡的增加而有增加之趨勢。

試驗二結果顯示，大型黑羽土雞無論是飼養在不同畜舍以及不同性別之間，雖然其體重的部分以飼養在水簾式畜舍之雞隻有較飼養在開放式畜舍重，且公雞顯著重於母雞，但是其相對增重方面則皆是無差異的，並且皆在雞隻飼養至11週齡時，其相對增重皆會降至10%以下，因此雞隻飼養至11週齡以後再繼續飼養下去，其生長效率會非常差，為了減少成本浪費，建議雞隻飼養至11週齡時即可上市。各部位生長發育方面，以內臟器官的發育為最早，接著是骨骼的生長，然後是肌肉的生長，最後則是脂肪的蓄積。生殖器官方面，以睪丸販賣之重量觀點來看，建議大型黑羽土雞之公雞在11週齡時即可上市；而以母雞之卵巢發育來看，建議大型黑羽土雞之母雞在性成熟(13週齡)以前上市。肌肉強度方面，大型黑羽土雞飼養至11週齡以後，其肌肉強度會變得較差，因此建議雞隻可在11週齡時上市。肌肉保水性方面，大型黑羽土雞之飼養全期，其肌肉保水性隨著週齡的增加並無明顯之變化。骨骼強度方面，隨著週齡的增加其脛骨長度及脛骨強度皆會隨之增加。脂肪酸方面，公雞屠體中的必需脂肪酸含量高於母雞；而雞隻屠體中之C18:2含量會隨著週齡的增加而有增加之趨勢。

整個試驗研究中顯示，在生長趨勢方面，冬季飼養之黑羽土雞其生長較夏季飼養好，水簾式畜舍有較開放式畜舍好之趨勢，且公雞生長較母雞好，但是在相對增重方面，無論是不同飼養季節、畜舍及不同性別之間則皆無差異，並且雞隻飼養至11週齡時，其相對增重皆會降至10%以下，此時雞隻之生長效率變差。黑羽土雞各部位之生長發育方面，內臟器官的發育主要是在4週齡以前；骨骼的生長主要發生在4至6週齡之間；肌肉的生長主要發生在7至10週齡之間；而脂肪的蓄積主要從10週齡以後開始，且隨著週齡的增加而持續增加。脂肪產量較高且較為肥胖的雞隻，其肌肉強韌度會減低；生長較快速且體重較重的雞隻，其脛骨強度會變差。冬季飼養之雞隻其脂肪組織中之C18:2含量會增加。雞隻隨著飼養週齡的增加，其屠體內之C18:2含量也會逐漸增加。必需脂肪酸(EFA)含量方面，以公雞屠體中的含量較母雞高。最後，以增重、睪丸、肌肉產量、肌肉剪力和肌肉保水性之觀點綜合來看，建議黑羽土雞約在11週齡即可上市。以屠體品質(屠體中脂肪酸組成)之觀點來看，建議中型黑羽土雞可在10至11週齡上市，而大型黑羽土雞可在11至12週齡上市。

關鍵字

屠體 ； 脂肪酸組成 ； 土雞 ； 季節

並列摘要

The objective of the study was to determine the effects of different season, housing, age on the carcass growth of black native chicken and fatty acid composition in carcass to understand the growth status of different body parts and changes in fatty acid composition in breast meat, thigh meat and leaf fat from young until mature. In Experiment 1, effects of different season, housing and age were studied on the growth performance, carcass characteristics and fatty acid composition of medium type black native chicken. The commercial medium type black native chicken was kept during winter and summer. Four thousand birds were kept during winter and summer, evenly allocated into two houses (wet pad housing and open type housing), two thousand birds in each house, the number of males and females was even and were kept separately. During the trial, feed and water were provided ad libitum. For every housing and sex treatment, 100 birds were selected and attached with leg bands, the birds were weighed weekly as the source for body weight data until the trial ended at 12 weeks of age. From 4-week until 12 week-old as the trial ended, 3 male and female birds from each housing
were sacrificed weekly to evaluate the growth status of different carcass parts, muscle shear force and water holding capacity, bone strength and fatty acid composition. In Experiment 2, the effects of different housing and age on the growth, carcass characteristics and fatty acid composition of large type black native chicken were studied. Four thousand commercial large type black native chickens were used, the treatments and management flow of the trial were similar as Experiment 1. The duration of the study commenced from post hatching until 13 weeks of age. From 4-week until 13-week old, the growth status of different body parts, muscle shear force and water holding capacity, bone strength and fatty acid composition measurements were similar as Experiment 1.

The results in trial 1 indicated that regardless of season, housing, and sexes, although medium type black native chicken in winter had significant heavier weight than those kept in summer, males were heavier than females, but relative weight gain was not significantly different. At 11-week old, relative weight gain reduced below 10%, hence, keeping the birds continuously after 11 weeks, growth rate was poor, considering economic purposes, the birds were suggested to be marketed at 11-week old. For the growth development in each part, the growth of the internal organs was the earliest, followed by bones, muscle and finally the deposition of fat. For reproduction organs, considering testis weight for market, it was proposed that medium type black native male chicken should be marketed at 11 to 12 weeks of age; for the growth of ovary, suggested medium type black native female chicken should be marketed before 12-week old. For muscle shear force, after keeping medium type black native chicken for 11 weeks, muscle shear force would not be higher, hence suggesting that the birds should be marketed at 11-week old; higher fat production from obese birds would lower muscle shear force. For water holding capacity, during the experimental period, medium type black native chicken muscle water holding capacity had no significant changes as the birds grew older. For bone strength, tibia length and strength increased as the age increased; fast growing and heavy birds had poorer bone strength. For FA, keeping chickens in cooler environment (winter and wet pad housing), C16:0 and C18:1 content in the thigh would increase; keeping chickens in winter would increase C18:2 in fat tissue; EFA in male carcass was higher than females, C18:2 content in carcass would increase as the age increased.

The results in trial 2 showed that regardless of housing and sexes, although large type black native chickens in wet pad housing had significant heavier weight than those kept in open type housing, males were heavier than females, but relative weight gain was not significantly different. At 11-week old, relative weight gain reduced below 10%, hence, keeping the birds continuously after 11 weeks, growth rate was poor, considering economic purposes, birds was suggested to be marketed at 11-week old. For the growth development in each part, the growth of the internal organs was the earliest, followed by bones, muscle and finally the deposition of fat. For reproduction organs, considering testis weight for market, it was proposed that large type black native male chickens should be marketed at 11 weeks of age; for the growth of ovary, suggested large type black native female chickens should be marketed before 13-week old. For muscle shear force, after keeping large type black native chicken for 11 weeks, muscle shear force became poor, hence suggested that the birds should be marketed at 11-week old; higher fat production from obese birds would lower muscle shear force. For water holding capacity, during the experimental period, medium type black native chicken muscle water holding capacity had no significant changes as the birds grew older. For bone strength, tibia length and strength increased as the age increased. For FA, EFA in male carcass were higher than female, C18:2 content in carcass would increase as the age increased.

The whole study indicated that for growth, black native chickens kept in winter were better than those kept in summer, wet pad housing was also tended to be better than open type housing, the growth for males was better than females, but for relative weight gain, regardless of season, housing and sexes, there no significant differences. At 11-week old, relative weight gain reduced below 10%, growth rate was poor. For the growth development of the carcass parts in black native chickens, the growth for internal organs was before 4-week old, bone growth took place between 4 to 6-week old; muscle growth happened mainly between 7 to 10-week old; while fat deposition commenced after 10-week old and would increase as the age increased. Higher fat production from obese birds would lower muscle shear force; fast growing and heavy birds had poorer bone strength. C18:2 content in the fat tissue from birds kept in winter would increase. As the age increased, C18:2 content in carcass would increase gradually. For EFA content, male was higher than female. Lastly, viewing from weight gain, testis, muscle production, muscle shear force and muscle water holding capacity, it was suggested that black native chicken could be marketed at 11-week old. For carcass quality (FA composition in carcass), it was suggested that medium type black native chicken could be marketed at 10 to 11-week old while that large type black native chicken could be marketed at 11 to 12-week old.

並列關鍵字

Carcass ； Fatty Acid Composition ； Native Chicken ； Season

參考文獻

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