Comparison of splanchnic tissues mass of two sheep breeds offered two diets differing in roughage level
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2009
Autores
Gomes, M.J.
Silva, Severiano
Azevedo, Jorge Manuel Teixeira de
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It is a general believe that the local sheep breed Churra da Terra Quente (CTQ), reared in the Northeast of
Portugal is well adapted to the conditions of its production system. However, there are large gaps on our
knowledge to allow understanding of such claimed adaptation. Splanchnic tissues (ST) can account for
35-50% of body energy expenditure, this high demand for energy being positively related with the protein
and cell turnover, which in turn allows adaptability and flexibility so that animals can respond to multiple
physiological and environmental challenges. The objective of the present study was to compare ST weights
of lambs from CTQ and from an exotic breed (Ile de France, IF) at the same mature body weight (MBW) and
fed two diets differing in roughage level. The study was carried out with 15 female lambs from each of the
two breeds. Initial body weight was 20.7±1.3 and 34.0±0.7 kg, for CTQ and IF respectively, corresponding
to ca 45% of their MBW. Animals were assigned to be slaughtered as an initial group or when they reached
ca 65% of their MBW, after being fed ad libitum a high (HR, 70% of meadow hay) or a low-roughage diet
(LR, 25% of meadow hay), according to a 2x2 factorial design. ST were removed and weighed. Per kg empty
BW, CTQ had higher weights of small intestine, large intestine, liver and total ST (P<0.05), the weights of
rumen-reticulum and omasum being higher only at 65% of MBW (P<0.01). Weights of the rumen-reticulum,
omasum, large intestine and total ST were higher (P<0.001) in sheep fed HR diet irrespective of breed, but
no differences were observed for the weight of abomasum, small intestine and liver (P<0.05). This study
confirms the existence of differences on relative weights of ST between sheep breeds at the same level of
maturity and between animals fed diets with different roughage levels. In conclusion, the high ST weights
of the local breed may lead to enhanced adaptation ability to its environment.