Whole genome scan reveals the genetic signature of African Ankole cattle breed and potential for higher quality beef

BACKGROUND: Africa is home to numerous cattle breeds whose diversity has been shaped by subtle combinations of human and natural selection. African Sanga cattle are an intermediate type of cattle resulting from interbreeding between Bos taurus and Bos indicus subspecies. Recently, research has asserted the potential of Sanga breeds for commercial beef production with better meat quality as compared to Bos indicus breeds. Here, we identified meat quality related gene regions that are positively selected in Ankole (Sanga) cattle breeds as compared to indicus (Boran, Ogaden, and Kenana) breeds using cross-population (XP-EHH and XP-CLR) statistical methods. RESULTS: We identified 238 (XP-EHH) and 213 (XP-CLR) positively selected genes, of which 97 were detected from both statistics. Among the genes obtained, we primarily reported those involved in different biological process and pathways associated with meat quality traits. Genes (CAPZB, COL9A2, PDGFRA, MAP3K5, ZNF410, and PKM2) involved in muscle structure and metabolism affect meat tenderness. Genes (PLA2G2A, PARK2, ZNF410, MAP2K3, PLCD3, PLCD1, and ROCK1) related to intramuscular fat (IMF) are involved in adipose metabolism and adipogenesis. MB and SLC48A1 affect meat color. In addition, we identified genes (TIMP2, PKM2, PRKG1, MAP3K5, and ATP8A1) related to feeding efficiency. Among the enriched Gene Ontology Biological Process (GO BP) terms, actin cytoskeleton organization, actin filament-based process, and protein ubiquitination are associated with meat tenderness whereas cellular component organization, negative regulation of actin filament depolymerization and negative regulation of protein complex disassembly are involved in adipocyte regulation. The MAPK pathway is responsible for cell proliferation and plays an important role in hyperplastic growth, which has a positive effect on meat tenderness. CONCLUSION: Results revealed several candidate genes positively selected in Ankole cattle in relation to meat quality characteristics. The genes identified are involved in muscle structure and metabolism, and adipose metabolism and adipogenesis. These genes help in the understanding of the biological mechanisms controlling beef quality characteristics in African Ankole cattle. These results provide a basis for further research on the genomic characteristics of Ankole and other Sanga cattle breeds for quality beef. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12863-016-0467-1) contains supplementary material, which is available to authorized users

Effect of finishing system on carcass characteristics and composition of Mubende goats and their Boer goat crossbreds

A study was conducted to evaluate the influence of feeding systems on carcass characteristics and composition of Mubende goats and their Boer goat crossbreds. A 2 x 3 factorial arrangement was used to randomly allocate 60 castrates, 30 purebred Mubende and 30 Mubende x Boer, aged 9 - 12 months, to three feeding systems: sole grazing (T1), grazing + non-molasses based concentrate (T2) and grazing + a molasses based concentrate (T3). Carcass measurements included carcass weights, carcass length, internal chest width, hind-limb length and maximum hind limb width. Tissue composition was estimated using the 6th rib. Crossbreds had heavier and longer carcasses (23.1 kg) and (65.7 cm) than the Mubende (19.0 kg and 63.2 cm), respectively. Crossbreds also had bigger hind quarters (39.0 cm) and higher blockiness (0.38) indices than Mubende goats, 37.1 cm and 0.29, respectively. Dissectible lean and fat percentages varied in an ascending order of 66%, 72%, 72.6% and 8%, 14% and 16.5% for T1, T2 and T3, respectively. A reverse trend was observed for bone percentages with carcasses from T1 having higher bone percentage (18.1%) than T2 (16.5%) and T3 (16.1%) irrespective of genotype. The study showed that supplementation of grazing goats has a great potential for goat meat production in Uganda.Keywords: Carcass characteristics, composition, indigenous goats, supplementatio

Sensory characteristics and tenderness of meat from Ankole bulls:influence of crossbreeding and feeding system

Eating-quality attributes of meat from Ankole cattle and their Friesian and Boran crossbreds finished in different feeding systems were evaluated. Seventy two 8-month-old bulls (24 each of pure Ankole (A), Ankole x Boran (B) and Ankole x Friesian (F) (191 ± 9.6 kg average weight) were allotted to three feeding systems in a completely randomized design with a 3 x 3 factorial treatment, and were slaughtered after 120 days. The longissimus dorsi muscle was excised from the carcasses and divided into five samples for sensory and shear force analysis. Samples aged 2, 7, 14 and 21days were subjected to the Warner Braztler shear force (WBSF) machine for textural tenderness determination. Steaks from Ankole and Friesian crossbreds attained WBSF values below 55N within 7 days of post mortem storage, whereas Boran crossbreds attained a similar level of tenderness at 14 days. Steaks from Ankole and Friesian crossbreds were rated more tender, juicy and acceptable than Boran crossbreds by panelists. Steaks from grazed bulls were rated less tender, juicy and palatable than steaks from supplemented and feedlot finished bulls. It was concluded that when grazed and supplemented or finished in a feedlot and meat aged for 7 days, Ankole bulls produce tender meat of an as high eating-quality as their Ankole x Friesian crossbreds.Keywords: Ankole cattle, crossbreds, feeding system, sensory scores, meat tendernes