نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده کشاورزی دانشگاه تهران. کرج. ایران
2 گروه علوم دامی، دانشکده کشاورزی، دانشگاه تهران، کرج، ایران.
3 گروه علوم دامی، دانشکده کشاورزی دانشگاه تهران.کرج. ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The aim of this study was to investigate the effects of dietry cation-anion difference (DCAD) levels and crossbreeding on carcass characteristics of lambs. In this study, 30 Lori Bakhtiari and first generation Lori Bakhtiari × Romanov × Pakistani lambs (50% Lori Bakhtiari, 25% Romanov, 25% Pakistani) with an average age of 90±10 days and an average weight of 33±1.5 kg were divided into two groups of 15 lambs, each group was fed with a different level of DCAD. Carcass weight, carcass yield, viscera weight, cross-sectional area of Longissimus muscle and carcass length did not show any significant difference between purebred and crossbreds and also between diets. Crossbreeding also significantly increased the weight of valuable and salable carcass parts (P<0.05). However, according to our findings, no difference was observed in terms of weight of salable carcass parts between anionic and cationic treatmentsgenotype and DCAD did not have any significant effect on the composition of carcass fatty acids. The meat shear force of Lori Bakhtiari × Romanov × Pakistani lambs compare to Lori Bakhtiari lambs and anionic diet compare to cationinc diet was lower (P<0.05). Lori Bakhtiari lambs had a higher mean in brightness index and Longissimus muscle redness than Lori Bakhtiari × Romanov × Pakistani lambs (P<0.05). Therefore, anionic diets and Crossbreeding can be considered as effective ways to increase the quality and crispiness of sheep meat.
کلیدواژه‌ها [English]
Extended Abstract
Introduction
Nowadays, crossbreeding is a common way to use genetic interactions between different breeds to increase production capacity. In recent decades, due to economic incentives, some flock owners have been using rams from heavy breeds, especially in small breed flocks. There is little information about the quantity and quality of performance of such crossbreds. As the genetic potential of the flocks raises, the adjustment of balanced diets, become very important. The balance of cations and anions such as sodium, potassium, chlorine and sulfur have a significant effect on the blood acid-base balance. In this case the requirements of sodium, potassium, chlorine and sulfur is not the only thing that is important, in fact, their balance is the point, that known as dietry cation-anion deference (DCAD). The aim of this study was to investigate the effects of DCAD and crossbreeding on carcass characteristics in the purebred and crossbred Lory Bakhtiari lambs .
Material and Methods
The present study was conducted for 12 weeks. 30 purebred and crossbred lambs with an average age of 90 days and average weight of 33.5 Kg, were divided into two groups of 15 lambs, each group fed with different levels of DCAD. Anionic diet was also applied in the last 20 days of the experiment.
Results.
Carcass weight, carcass efficiency, skin, full and empty rumen, lungs, kidneys, heart, liver and spleen weight, carcass length, and head and foot weight between purebred and crossbreds did not show significant differences (P>0.05). The intraocular fat weight in crossbreds was more than the purebreds (P <0.0001). Also, the cross-sectional area of Longissimus muscle in crossbreds showed a higher average, which tended to be significant (P = 0.06). In this study, it was shown that the characteristics of carcass are not affected by DCAD (P>0.05). The weight of valuable carcass parts was significantly higher in crossbreds(P>0.05). But crossbreednig did not make a significant difference in weight of the thigh muscle (P = 0.15). According to our findings, there was no difference in the weight of the carcass valuable parts between anionic and cation diets (P>0.05). The effect of crossbreeding on the chemical composition of the muscle was not significant (P>0.05). Also, the change in the DCAD level did not have a significant effect on the chemical composition of the muscle too (P>0.05).Also genetic and DCAD have no significant effect on the profile of carcass fatty acids (P>0.05). The shear force of meat of Lori Bakhtiari × Romanov × Pakistani breed was lower than Lori Bakhtiari breed (P=0.01). Also, feeding with anionic diet during the last 20 days of the period caused the meat of the Longissimus muscle become more crispy compared to the cationic diet (P<0.05). Lori Bakhtiari lambs had a higher mean in brightness index and Longissimus muscle redness than Lori Bakhtiari × Romanov × Pakistani lambs (P<0.05).
Conclusion
According to our findings, crossbreeding can be an effective method to increasing the profitability of sheep flocks through increasing the weight of valuable carcass parts and in parallel, reducing tail fat weight, which means that crossbreeding can Increase the efficiency in fatty tailed sheep flocks. The results show that the use of crossbreeding, made the meat of fattening lambs more crispy and improve its quality. Also, using anionic ration in the last two weeks of the fattening period can be a nutritional strategy to improve meat quality and crispness.
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