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Original Research
5.
Evaluation of in vitro gas production and nutrient
digestibility of complete diets supplemented with
different levels of thermotolerant yeast in nellore
rams -
Ch. Harikrishna, M Mahender, Y Ramana Reddy, M Gnana
Prakash, K Sudhakar, M Pavani
Vet World. 2012; 5(8): 477-485
doi:
10.5455/vetworld.2012.
477-485
Abstract
Aim:
The objective of the present study was to know the
effect of dietary supplementation of varied levels
of thermotolerant yeast to determine best levels for
sheep diets by in vitro gas production. An in vivo
study on Nellore rams was used for further
evaluation of diets with three best levels of yeast
(obtained from in vitro data) to determine diet with
optimum yeast level for growing lambs by assessing
nutrient digestibility, plane of nutrition and
nitrogen balance.
Materials and Methods: A
complete diet was formulated and supplemented with
five levels (0 g/kg (D1); 1 g/kg (D2); 2 g/kg (D3);
3 g/kg (D4); 4 g/kg (D5) and 5 g/kg (D6) of
thermotolerant yeast (Saccharomyces cerevisiae,
OBV-9) @ 5x108 cfu/g to determine best levels for
sheep diets by IVGP technique. An in vivo study was
conducted on Nellore rams (39.75 0.24 kg body
weight, aged 3 years) in a 4 x 4 latin square design
for further evaluation of diets with three best
yeast levels based on in vitro data, to determine
optimum yeast level for diets of growing lambs by
assessing nutrient digestibility, plane of nutrition
and nitrogen balance. The rams were housed
individually in metabolic cages that allowed
separation of urine and faeces to evaluate
digestibility of nutrients and N balance. Animals
were given 10 days adaptation period followed by
7-day collection period, feed intake and refusals
were recorded. During the digestibility and N
balance study, feed, refusals and faeces were
analyzed for dry matter (DM), organic matter (OM)
and crude protein (CP) as per AOAC, USA, while fibre
fractions like neutral detergent fibre (aNDF) and
acid detergent fibre (ADF) were analyzed. Data were
analyzed as per the procedures suggested by Snedecor,
G. W. and Cochran, W. G. (1994) and the difference
between treatment means was tested for significance
by Duncan's multiple-range and F Test.
Results:
Higher (P<0.01) IVGP volumes, in vitro organic
matter degradability, metabolizable energy (ME) and
total degradable organic matter were recorded for
rations D2 to D6 over control, whereas the
difference among D2 to D4 diets was not significant.
Significant (P<0.05) partitioning factor and
efficiency of microbial biomass synthesis (EMBP)
values for rations D2 and D3 and significant
(P<0.01) microbial biomass production for D2 to D6
diets, recorded. Significant (P<0.01) nitrogen (N)
retention was recorded in yeast supplemented rations
with high EMBP than control. Dry matter intake (DMI),
DMI (% b. wt.), DMI/kg W0.75 and the digestibility
of dry matter, organic matter, crude protein, crude
fibre, ether extract (P<0.05), nitrogen free extract
and fiber fractions were significant (P<0.01) on
rations D2 to D4 over control, while the difference
among rations D2 to D4 was not significant. All rams
were in positive N balance and was higher (P<0.01)
on rations D2 to D4 over control. The digestible
crude protein (DCP) and ME were higher (P<0.01) on
rations D2 to D4 indicating all rams were adequately
met with DCP and ME requirements as suggested by
ICAR, India. Conclusions: The present study
demonstrated the potential of theromotolerant yeast
at 1 g/kg to 3g/kg level in improving digestibility
of nutrients, intake of DCP and ME and N retention
without affecting health of rams under study. Thus,
incorporation of 1 g/kg level of thermotolerant
probiotic yeast in complete diet for lambs appears
to be beneficial for livestock producers.
Keywords: Nellore rams, Thermotolerant yeast, In
vitro gas production, Digestibility, N retention.
