Growth Performance and Meat Characteristics of the First Awassi–Rambouillet Callipyge Backcross

Abstract

The Awassi breed is desirable due to its resilient traits, but shows poor lean meat content on the carcass; the callipyge mutation may enhance growth and meat characteristics. The first backcross of callipyge Awassi–Rambouillet (CRAW) lambs was generated by mating Awassi ewes with heterozygous F1 (50 % Awassi and 50 % Rambouillet) rams for the callipyge mutation. A fattening trial with carriers of CLPG (CRAW), non-carriers (RAW), and Awassi (AW) ram lambs was conducted for 94 days and growth and meat characteristic parameters were recorded. Final body weight, average daily gain (ADG), feed conversion ratio, and dry matter intake, but not initial body weight, were greater in CRAW and RAW lambs as compared to AW lambs; hot and cold carcass, dressing percentage, and shoulder, rack, and loin weights were greater in CRAW vs. AW but not RAW lambs. Leg cuts were heavier in CRAW vs. both RAW and AW lambs; intermuscular and subcutaneous fat percentages were greater in CRAW as compared to AW but not RAW lambs. Non-carcass components showed kidney fat, kidney, liver and testes weights higher in CRAW lambs as compared to AW lambs, but these parameters were similar to those of RAW lambs. There were no differences in fat tail weight. Further, CRAW lambs had higher shear force and water holding capacity than RAW and AW lambs, while cooking loss was the lowest in CRAW lambs. In conclusion, the callipyge mutation with 25% Rambouillet genes can provide efficient improvements in growth and meat characteristics, with the exception of tenderness in Awassi sheep.

Relationships between Hha1 Calpastatin Gene Polymorphism, Growth Performance, and Meat Characteristics of Awassi Sheep

“…At the end of the fattening period, all lambs were slaughtered for the evaluation of carcass traits and meat quality, as previously described [10,11,12]. Briefly, carcasses were divided into four parts, namely shoulder, rack, loin, and leg cuts, in addition to the fat tail and the rib-eye area, fat depth, tissue depth, rib fat depth, eye muscle width, eye muscle depth, eye muscle area, and leg fat depth, measured as previously described [10,12]. The right leg was dissected to determine muscle, bone, subcutaneous fat, and intermuscular fat components.…”

“…Longissimus muscles were excised from the right side of loin cuts, cleaned from all subcutaneous fat, vacuum-packaged, and frozen at −20 °C for meat quality measurements, as described [13]. Meat quality parameters were Warner–Bratzler shear force values for cooked meat samples, water holding capacity, cooking loss, and color coordinates (whiteness, redness, yellowness) [10,12,13].…”

Akkaraman Koyun Irkında Callipyge Gen Polimorfizmin Araştırılması

“…The CLPG causes muscle hypertrophy that is restricted to the pelvic and lumbar muscles with little or no effect on the anterior skeletal muscles (Cockett et al, 1996). As described in several studies, this gene also provides a higher leg score and carcass percentage, larger longissimus loins, superior leanness composition, higher leg values, higher percentage of dressing percentages, and optimal feed conversion, as well as higher body weight and Baron-Crevat indices (Jackson et al, 1997;Jawasreh et al, 2019;Esen et al, 2022b).…”

Fattening performance and carcass traits of two fat tailed sheep breeds

“…In addition, Longissimus muscle area for Awassi, Tushin and Red Karaman fat tailed breeds was similar(Esenbuga et al, 2001). Meanwhile, Longissimus muscle area, width, and depth were found to differ among three different lamb genotypes(Jawasreh et al, 2019).…”

“…Al. (2019) reported that all measurement of fat thickness were affected by lamb's genotype when comparing Awassi to Awassi crossbred lambs(Jawasreh et al, 2019). In addition, Longissimus muscle area for Awassi, Tushin and Red Karaman fat tailed breeds was similar(Esenbuga et al, 2001).…”