Histochemical characteristics of the muscle and pH of hybrid rabbits meat slaughtered at different ages

Abstract:

To study the effects of genetic type, different slaughtering ages (75, 85 and 95 days) and sex on pH of muscles Biceps femoris, Latissimus dorsi and Soleus (45 min. and 24 h post mortem) and on the level of collagen in lumbar muscle (Longissimus lumborum), 60 hybrid rabbits (30 Hyla, 30 Provisal) were used. On 18 male rabbit carcasses (3 ages x 2 genetic types) histochemical characeristics, fibre diameter and fibre/connective tissue ratio were determined in these same muscles.

Percentages of the different fibre type are not influenced by the slaughthering ange, whilst important differences (P<0.05) were recorded between genetic lines for all fibre types. The percentage of I and IIA fibre in the Biceps femoris and Latissimus dorsi is particulary higher in Hyla than in Provisal, whilst the contrary is recorded for IIB fibre. On the contrary, for Soleus muscle the percentage of I fibre is high in Provisal, and IIA fibre high in Hyla. 

In Latissimus dorsi, Biceps femoris and Soleus muscles the fibre diameter increase with age (P<0.05). The percentage of connective tissue decrease with age (P<0.01) as the collagen content (endomysium et périmysium) of the lumbar muscles (P<0.05). Apart from the muscle type and the moment of record (45 min or 24 h pos mortem) the considered variables do not influence pH values.

The results show:

- Between 75 and 95 days the characteristics of the muscle growth are the increase of all the types muscles sizes and the decrease of the connective tissue.

- The genetic type influence the fibre composition of the muscle which may be improve by selection.

- Sex, slaugthering age and genetic type doesn't influence meat pH of the rabbit used.

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