Physical, chemical and histological characreistics of rahmani and ossimi lambs with particular reference to longissimus dorsi and biceps femoris muscles

الملخص EN

Eight male lambs each of Egyptian Rahmani and Ossimi breeds were used to study the effect of breed and age at slaughter on the chemical characteristics of meat in relation to histological traits.

Lambs were weaned at four months of age and fed according to their weight on concentrate feed mixture and Egyptian clover or its hay.

Four lambs per breed were slaughtered at 9 and 12 months of age.

Longissimus dorsi (L.

dorsi) at the 9th, 10th and 11th ribs (rib cut) and the Biceps femoris (B.

femoris) muscles were separated from the right half of the carcass for chemical analysis and histological study.

Samples of these muscles were divided into two parts, these for chemical analysis were dried off, while those for histological study were fixed in 10 % formol saline.

Histological characteristics considered were number and diameter of muscle fibers, bundle and stroma section area and bundle: stroma.

Physical (area of L.

dorsi and proportion of lean, bone and fat), and chemical characteristics (moisture, ether extract, protein and ash) were measured in the rib cut.

Breed had no effect on area of L.

dorsi and slaughter weight.

Physical components of rib cut showed that fat percentage was lower (P<0.01) in Rahmani than in Ossimi by 5.9 % with no significant difference between the two breeds in the percentage of lean, bone and boneless meat.

Meat chemical analysis indicated that moisture percentage was higher (P<0.01) and fat percentage lower (P<0.0001) in Rahmani than in Ossimi, while no difference in ash and protein percentages was recorded.

Except number of fibers which was higher (P<0.05) in Ossimi than in Rahmani, no difference was found in all histological traits between the two breeds.

Slaughter weight was higher (46 kg) at age of 12 months over that at 9 months (31.4 kg).

Area of L.

dorsi, ash and protein contents as well as histological traits increased slightly, while moisture decreased (P<0.0006) and fat increased (P<0.0001) as age progressed.

L.

dorsi had higher (P<0.0001) percentages of ash, fat, and protein but lower moisture (P<0.0001) than B.

femoris.

Type of muscle indicated that B.

femoris was higher (P<0.0001) in the number & diameter of fibers, bundle and stroma areas compared to L.

dorsi.

In conclusion, Rahmani lambs had significantly lower intra-muscular fat percentage compared to Ossimi.

Similar trend was observed in the carcass of lambs slaughtered at 9 compared to 12 months of age.