52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
EFFECT OF PROTEIN LEVELS ON RUMINAL DIGESTIBILITY AND INTAKE OF
GROWING BUFFALO¹
Érica Machado², Lúcia Maria Zeoula², Emerson Henri Yoshimura²,Rafael Barreiros Samensari²,
Nadine Woruby Santos², Lucelia de Moura Pereira², Bruna Calvo Agustinho²
¹ Part of the first author's dissertation, funded by CNPq
² Department of Animal Science, State University of Maringa, Maringa, PR [email protected]
Resumo: Objetivou-se avaliar os efeitos de níveis de proteína na dieta (70, 90, 110, e 130 g/kg de
MS)sobre a digestibilidade ruminal e ingestão de nutrientes em búfalas em crescimento . Foram
utilizadas quatro búfalas com cânulas no rúmen, com peso vivo médio inicial de 355 ± 3,5 kg,
distribuídas em um quadrado latino (4 × 4) com quatro animais e quatro tratamentos. As dietas foram
compostas de silagem de milho e concentrado e foram formuladas para atender os níveis propostos de de
proteína. As dietas foram fornecidas ad libitum para permitir 5 a 10 % de sobras. Verificou-se que os
níveis crescentes de proteína na dieta aumentaram linearmente o consumo de matéria seca e dos
nutrientes. Também aumentos lineares nas digestibilidade ruminal da matéria seca e proteína no rúmen
foram observados. Entretanto, em todos os níveis de proteína na dieta (70, 90, 110, e 130 g PB/kg de
MS) os coeficientes de digestibilidade ruminal da fração fibrosa e da matéria orgânica foram
semelhantes. Assim, estes resultados sugerem que o nível CP na dieta de 70 g/kg MS em relação aos
maiores níveis de proteína dietética avaliados foi adequado ao crescimento microbiano pela ausência de
diferença na digestibilidade ruminal da parede celular, porém o aumento na disponibilidade de energia
para o animal foi observado no maior nível de proteína.
Palavras–chave: Bubalinos, Proteína, Rúmen
Abstract: The objective was to evaluate the effects of protein levels in the diet (70, 90, 110, and 130 g /
kg DM) on ruminal digestibility and nutrient intake in buffalo growing. Four buffaloes were used, with
cannulas in the rumen, with average weight of 355 ± 3.5 kg were allotted in a Latin square (4 × 4) with
four animals and four treatments. The diets were composed of corn silage and concentrate and have been
formulated to meet the proposed levels of protein. The diets were fed ad libitum to allow 5 to 10% of
leftovers. It was found that increasing levels of protein in the diet linearly increased dry matter intake and
nutrients. Also linear increases in ruminal digestibility of dry matter and protein were observed.
However, in all levels of protein in the diet (70, 90, 110, and 130 g CP / kg DM) ruminal digestibility of
fiber fraction and organic matter were similar. Thus, these results suggest that the CP level in the diet of
70 g / kg DM compared to higher levels of dietary protein was evaluated suitable to microbial growth as
no significant difference in the rumen digestibility of the cell wall, but the increased availability of
energy for The animal was observed at the highest level of protein.
Keywords:Buffaloes, Protein, Rumen
Introduction
Ruminant animals, despite similarities in their digestive physiology, its functionality is not exactly
the same in all species, since there are unique physiological and behavioral characteristics of each specie.
The buffaloes are more efficient in nitrogen recycling process and also has higher intake in food systems
a predominance of grasses and better digestibility compared to cattle (Vega, 2010).
Dietary protein promotes differentiated gains on animal performance, and also increases ruminal
conditions for the developments of microorganisms, which consequently provides improved energy
extraction of fibrous fraction of food (Salvador et al., 2008).
The limitation of digestibility is determined by the microbial requirements and efficient use of
recycled nitrogen. There is, however a level below which recycling does not satisfies microbial
requeriments, and according to Van Soest (1994), this level would be approximately 6 to 8% PB.
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Therefore protein deficiency in the diet may limit microbial growth, reduce food intake, and reduce the
digestibility of the cell wall, and hence affect animal performance.
The ruminal digestibility of CP of diet influences both the ruminal fermentation as the amino acid
supply for the small intestine. So, the efficiency of rumen fermentation is crucial to provide
metabolizable protein for the animals and meet their nutritional requirements.
Thus the objective was evaluate the inclusion of CP levels in the diet of buffalo females growing on
the intake and ruminal digestibility of nutrients
Material e Methods
The experimental protocols that were developed in this study fully complied with the ethical
principles of animal experimentation prepared by the Brazilian College of Animal Experimentation COBEA and were referred to the Ethics Committee on Animal Use in Experimentation, State University
of Maringa, for consideration under the number approval 009/2013.
Four female crossbred buffaloes (Murrah × Jaffarabadi) with an average body weight of 355.00 ±
3.50 kg (18 months old) with cannulas in the rumen were distributed in a Latin square (4 × 4), with 4
animals, 4 time periods, and 4 diets (70.00, 90.00, 110.00, and 130.00 g CP/kg DM). The treatments that
were analyzed differed in their levels of crude protein. Diets were composed of 85% of corn silage and
15 % of concentrate and were formulated to meet the proposed levels of protein; the feed was provided
ad libitum to allow for 50.00 to 100.00 g/kg DM of orts.
The experimental period extended for 76 days and was divided into 4 time periods of 19 days
each, with 14 days for acclimation to the diets and 5 days for data collection. The feed and orts were
sampled during the collection periods and were stored in plastic bags and frozen for further analyses.
The collection of omasum digesta was performed by suction, according to the technique
described by Huhtanen et al. (1997), at intervals of 27 hours for 5 days. For the determination of the daily
flows of dry matter in the omasum we used chromic oxide as an external marker, which was supplied
intra-ruminally in two doses of 5.00 g each day (at 8 h and 16 h); the doses were previously weighed and
packed in hygroscopic paper. The concentrations of chromium oxide in the samples of omasal digesta
and feces were determined by atomic absorption spectrophotometry according to the method proposed by
Williams et al. (1962).
The DM of was determined in a forced-air oven according to AOAC procedure 934.01 (1990).
The ash content determined by combustion at 600 ° C for 6 hours according to the AOAC method 924.05
(1990). The determining total N followed the procedure paragraph 990.03 of AOAC (1990). The acid
detergent fiber concentrations (FDA) were determined according to the AOAC procedure paragraph
973.18 (1990). The ether extract (EE) was determined in accordance with paragraph procedure 7060
AOAC (1990).
The statistical analysis of the variables that were studied was interpreted by using the PROC
MIXED of SAS (Statistical Analysis System, version 9.2.). We used a 4 × 4 Latin square experimental
design with four animals and four diets, according to the following model:
Yijk = µ + Ai + Pj + Tk + eijk, where:
Yijk = observed variable; µ = general mean; Ai = animal effect of i, ranging from 1 to 4;
Results and Discussion
The increased levels of dietary protein had a positive effect (P < 0.05) on the intake of dry
matter, organic matter, CP, NDF, and ADF (Table 1). Therefore each 1% increase in dietary CP resulted
in a linear increase of 0.24 % of intake of DM and 0,58 % of ruminal digestibility of DM. Although the
pattern of intake showed positive linear behavior (P < 0.01) with the increase of protein intake should be
highlighted that the greatest difference was between the lowest level of dietary protein in relation to
others levels. This can be explained by the regression equation with relatively low coefficient of
determination (average of R2 = 0.77), except protein intake with the highest value for R2.
Critical levels of protein intake causes a decline in voluntary food intake, although for ruminants,
the critical level is lower due to the protein contribution of rumen microflora and the recycling of
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
nitrogen. However, the results indicate that the levels of CP used did not cause injury to the development
of rumen microorganisms, since there was no effect on ruminal digestibility of fibrous fractions (NDF
and ADF) and of organic matter.
Also, Van Soest (1994) reported that when the supply of nitrogen from the rumen does not meet
the requirements of rumen microorganisms, microbial growth can be limited and affect cell wall
digestibility and consequently affect the intake as well. Besides, revealed that a CP content below 70.00
g/kg in the diet affected the digestibility of fiber, while a CP content above this value did not change this
parameter. Therefore, the results obtained are in accordance with this information.
Table 1. Averages, regression equations (RE), coefficient of determination (R²), standard
error of mean (SEM) and effect of CP levels (P) or linearly (L) or quadratic (Q) on the intake
(kg/day) and ruminal digestibility (kg/kg) of Dry Matter and nutrients in crossbred buffaloes
Item
Intake
Ruminal Digestibility
Intake
Ruminal Digestibility
Intake
Ruminal Digestibility
Intake
Ruminal Digestibility
Intake
Ruminal Digestibility
Crude protein level (g/ kg)
RE
70
90
110
130
Dry Matter
5.58
6.76
6.99
7.09
1
0.51
0.59
0.61
0.62
2
Organic Matter
5.35 6.43 6.65
6.73
3
0.58 0.60 0.60
0.61
ns
Crude Protein
0.40 0.62
0.78
0.96
4
- 0.32 0.07
0.26
0.28
5
Neutral Detergent Fiber
2.85
3.41
3.52
3.55
6
0.58
0.60
0.61
0.61
ns
Acid detergente fiber
1.46
1.81
1.88
1.91
7
0.45
0.51
0.48
0.46
ns
SEM
P
CP
L
Q
0.25
1.56
< 0.01
0.05
<0.01
<0.01
0.31
0.11
0.23
1.32
<0.01
0.11
<0.01
0.21
0.33
0.18
0.06
7.31
<0.01
<0.01
<0.01
<0.01
0.34
0.21
0.13
0.92
<0.01
0.37
<0.01
0.25
0.10
0.20
0.07
1.12
<0.01
0.13
<0.01
0.89
0.10
0.09
1-Y = 4.22 + 0.24X R² = 0.80;2 - Y=4.67 + 0.58X R² = 0.76; 3- Y = 4.11 + 0.22X R² = 0.78; 4 - Y = 0.24 + 0.09X R² = 0.99; 5 - Y =
106.49 + 1.68X R² = 0.94; 6 - Y = 4.21 + 0.24X R² = 0.74; 7- Y = 2.26 + 0.11X R² = 0.77 ;ns – not significant.
Conclusions
The results suggest that the lowest CP level in the diet (70.00 g/kg) was adequate for promoting
microbial growth but at the highest level allowed for greater intake of nutrients in buffalo at growth.
References
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