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Abstract
Three independent
studies using male Kajli lambs at post-weaning, growing and
finishing stages were designed and undertaken to examine the effect
of different protein sources with or without probiotics on growth
performance and carcass characteristics. In the trial I, 32 male
Kajli lambs at three months age were randomly divided into eight
groups of four animals each in a 4×2 factorial arrangement. Four iso-caloric
(70% TDN) and isonitrogenous (22% CP) diets were formulated with
four different protein sources i.e. corn gluten meal 30% (CGM),
canola meal (CM), cotton seed meal (CSM) and sunflower meal (SFM)
containing either 0 or 50g of probiotics (Protexin®)/ ton of feed.
In trial II and III, lambs were again randomized and given the same
treatment as in trial I. However, crude protein (CP) content of
diets was reduced from 22 to 18% in trial II and 18 to14% in trial
III. In trial I, higher (P<0.05) dry matter (DM) and CP intake, DM,
CP, neutral detergent fibre (NDF) and acid detergent fibre (ADF)
digestibility, blood glucose, N-balance and total weight gain were
observed in lambs fed CM diet than those fed CGM, CSM and SFM diets.
However, blood urea nitrogen (BUN), creatinine and serum minerals
remained unaltered (P>0.05) in lambs fed diets containing different
protein sources. Neutral detergent fibre and ADF digestibility and
blood glucose was higher (P<0.05) in lambs fed diets containing
probiotics. Dry matter and CP intake and their digestibility, BUN,
creatinine, serum minerals, N-balance and total weight gain remained
unaltered (P>0.05). In trial II, higher (P<0.05) DM and CP intake,
blood glucose, N-balance and total weight gain were noticed in lambs
fed CM diet than those fed CGM, CSM and SFM diets.However, diets
containing different protein source didn’t affect (P>0.05) the DM,
CP, NDF and ADF digestibility, BUN, creatinine and serum minerals.
Neutral detergent fibre and ADF digestibility and total weight gain
was higher (P<0.05) in lambs fed diets containing probiotics.
However, diets containing probiotics didn’t influence (P>0.05) DM
and CP intake, DM and CP digestibility, BUN, blood glucose,
creatinine, serum minerals and N-balance. In trial III, higher
(P<0.05) DM and CP intake, N-balance and total weight gain were
observed in lambs fed CM diet than those fed CGM, CSM and SFM diets.
However, DM, CP, NDF and ADF digestibility, BUN,blood glucose,
creatinine and serum minerals remained unaltered (P>0.05) in lambs
fed diets containing different protein source. Acid detergent fibre
digestibility and total weight gain was higher (P<0.05) in lambs fed
diets containing probiotics however, DM and CP intake, DM, CP and
NDF digestibility, BUN, blood glucose, creatinine, serum minerals
and Nbalance remained unaffected (P>0.05). Hot carcass weights of
lambs differed significantly (P<0.05) in lambs fed diets containing
different protein sources with or without probiotics. However,
dressing percentage (DP) and skin, feet, heart, liver and lungs
weight remained unaltered (P>0.05) across all the treatments. The
higher DP was observed in lambs fed CM diets, whereas it was lower
in lambs fed SFM diet. Leg, loin, shoulder, breast and neck weights
of the half carcass of the lambs remained unaffected (P>0.05) across
all the treatments. Crude protein content of carcass was different
(P<0.05) in lambs fed diets containing different protein source with
or without probiotics, while moisture, ether extract and ash
contents remained unaltered (P>0.05) across all treatments.The ratio
of lean, fat and bone in primal cuts of half carcass (neck,
shoulder, breast, loin and leg) remained unchanged (P>0.05) across
all the treatments, except for the proportion of lean in shoulder,
bone in loin and fat in legs, which was affected (P<0.05) by the
diets containing different protein sources. In short, the lambs fed
CM diets performed better than those fed CGM, CSM and SFM diets in
all the three trials. Diets containing probiotics improved weight
gain in trial II and III but not in trial I. |
