Efeito da adição de nitrato encapsulado na alimentação de bovinos de corte durante recria e terminação em pastejo
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Data
2017-10-27
Autores
Fenandes, Rodolfo Maciel
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se com a presente pesquisa avaliar se o consumo de nitrato encapsulado por bovinos zebuínos nas condições tropicais em pastejo da recria ao abate altera os parâmetros ruminais, consumo, mitiga metano, altera o desempenho, a qualidade da carne e ocasiona resíduo na carne. Foram utilizados 96 animais da raça Nelore com idade entre 7 e 8 meses e 197 ± 15,3 kg de peso corporal (PC) inicial, distribuídos aleatoriamente em blocos completos ao acaso aos tratamentos para a avaliação de desempenho, sendo que desses, 24 animais foram utilizados para a avaliação da emissão de metano. Também foram utilizados 12 animais contemporâneos dos animais de desempenho com fistulados no rúmen e PC inicial de 202 ± 6,22 kg para a quantificação dos parâmetros fermentativos, distribuídos aleatoriamente em blocos completos, totalizando 108 animais. Foram avaliados dois tratamentos, o primeiro denominado controle (suplemento sem nitrato, com equivalente proteico substituído por ureia) e o segundo, suplemento com nitrato (47g NO3-/100 kg PC). O experimento foi dividido em três fases: seca (07/2014 a 11/2014), águas (11/2014 a 05/2015) e terminação (05/2015 a 09/2015). Na fase de seca, a suplementação com nitrato reduziu a concentração de NAR (P≤0,04) em média 39%, 6, 12 e 18 horas após a suplementação. Na fase de águas e terminação, o nitrato ocasionou menor concentração de NAR 6 horas após a suplementação na proporção de 29,62% e 60,73%, respectivamente (P=0,06). O uso de nitrato aumento o consumo de forragem dos animais apenas na fase de águas (P=0,04) em 1,30kg/dia. Nas fases de seca e águas, a suplementação com nitrato tendeu (P≤0,11) a reduzir a emissão de metano em aproximadamente 16,57% e 14,59%, respectivamente. Apenas na fase de terminação houve efeito do tratamento (P=0,03) sobre o ganho de peso, com médias de 0,901kg/dia para animais recebendo controle e 0,998kg/dia para animais suplementados com nitrato, proporcionando animais com peso superior ao abate (492kg para animais controle e 521kg para animais nitrato) (P=0,05). Não houve efeito dos tratamentos no peso de carcaça final (P=0,44), com médias de 297kg e 303kg para animais controle e nitrato, respectivamente. A carcaça dos animais controle tiveram maior espessura de gordura subcutânea (3mm) em relação a nitrato (2,1mm) (P=0,08). Houve tendência em reduzir a intensidade de emissão (g/kg de carcaça) em 18% nos animais nitrato(P=0,11). Não houve diferença entre os tratamentos para qualidade e cor da carne (P≥0,32) e também no perfil de ácidos graxos (P≥0,50). O uso de nitrato não proporciona resíduo de nitrato na carne (P=0,77). Conclui-se que o consumo de nitrato encapsulado por bovinos zebuínos nas condições tropicais em pastejo da recria ao abate pode alterar os parâmetros ruminais, o consumo de forragem e tende a reduzir a emissão de metano de acordo com a qualidade da forragem. O consumo de nitrato encapsulado também proporciona peso superior ao abate, sem alterar o peso de carcaça final, além de não alterar a qualidade ou deixar resíduo na carne.
The objective of this research was to evaluate if the intake of nitrate encapsulated by zebu cattle in the tropical conditions under pasture grazing changes the ruminal parameters, consumption, mitiga methane, changes in performance, meat quality and cause s residue in meat. A total of 96 Nellore animals aged 7 to 8 months and 197 ± 15.3 kg of body weight (BW) were randomly assigned in randomized complete blocks to treatments for performance evaluation, of which 24 animals were used for the evaluation of met hane emission. We also used 12 contemporary animals from performance animals with rumen fistulae and initial CP of 202 ± 6.22 kg for the quantification of fermentative parameters, randomly distributed in complete blocks, totaling 108 animals. Two treatment s were evaluated, the first one called control (supplement without nitrate, with protein equivalent substituted by urea) and the second supplement with nitrate (47g NO3 - / 100kg PC). The experiment was divided into three phases: dry (07/2014 to 11/2014), w ater (11/2014 to 05/2015) and termination (05/2015 to 09/2015). In the dry phase, nitrate supplementation reduced the RAN concentration ( P≤0.04 ) on average by 39%, 6, 12 and 18 hours after supplementation. In the water and termination phase, nitrate caused a lower concentration of RAN 6 hours after supplementation in the proportion of 29.62% and 60.73%, respectively ( P=0.06 ). The use of nitrate increased the forage intake of the animals only in the water phase ( P=0.04 ) in 1.30 kg / day. In the drought and w ater phases, nitrate supplementation tended to reduce methane emissions by approximately 16.57% and 14.59%, respectively ( P≤0.11 ). Only in the termination phase was treatment effect ( P = 0.03) on weight gain, with averages of 0.901 kg / day for animals rec eiving control and 0.988 kg / day for animals supplemented with nitrate, providing animals with higher XIV slaughter weight (492 kg for control animals and 521 kg for nitrate animals) ( P=0.05 ). There was no effect of treatments on final carcass weight ( P=0.44 ) , with averages of 297kg and 303kg for control and nitrate animals, respectively. The carcass of the control animals had a higher thickness of subcutaneous fat (3mm) in relation to nitrate (2.1mm) ( P=0.08 ). There was a tendency to reduce the emission intensity (g / kg of carcass) by 18% in nitrate animals ( P=0.11 ). There was no difference between the treatments for meat quality and color ( P≥0.32 ) and also in the fatty acid profile ( P≥0.50 ). The use of nitr ate does not provide nitrate residue in meat ( P=0.77 ). It can be concluded that the consumption of nitrate encapsulated by zebu cattle under tropical conditions under pasture grazing at slaughter can alter ruminal parameters, forage consumption and tends t o reduce methane emissions according to forage quality. The consumption of encapsulated nitrate also provides superior slaughter weight, without altering the final carcase weight, and does not alter the quality or leave residue in the meat.
The objective of this research was to evaluate if the intake of nitrate encapsulated by zebu cattle in the tropical conditions under pasture grazing changes the ruminal parameters, consumption, mitiga methane, changes in performance, meat quality and cause s residue in meat. A total of 96 Nellore animals aged 7 to 8 months and 197 ± 15.3 kg of body weight (BW) were randomly assigned in randomized complete blocks to treatments for performance evaluation, of which 24 animals were used for the evaluation of met hane emission. We also used 12 contemporary animals from performance animals with rumen fistulae and initial CP of 202 ± 6.22 kg for the quantification of fermentative parameters, randomly distributed in complete blocks, totaling 108 animals. Two treatment s were evaluated, the first one called control (supplement without nitrate, with protein equivalent substituted by urea) and the second supplement with nitrate (47g NO3 - / 100kg PC). The experiment was divided into three phases: dry (07/2014 to 11/2014), w ater (11/2014 to 05/2015) and termination (05/2015 to 09/2015). In the dry phase, nitrate supplementation reduced the RAN concentration ( P≤0.04 ) on average by 39%, 6, 12 and 18 hours after supplementation. In the water and termination phase, nitrate caused a lower concentration of RAN 6 hours after supplementation in the proportion of 29.62% and 60.73%, respectively ( P=0.06 ). The use of nitrate increased the forage intake of the animals only in the water phase ( P=0.04 ) in 1.30 kg / day. In the drought and w ater phases, nitrate supplementation tended to reduce methane emissions by approximately 16.57% and 14.59%, respectively ( P≤0.11 ). Only in the termination phase was treatment effect ( P = 0.03) on weight gain, with averages of 0.901 kg / day for animals rec eiving control and 0.988 kg / day for animals supplemented with nitrate, providing animals with higher XIV slaughter weight (492 kg for control animals and 521 kg for nitrate animals) ( P=0.05 ). There was no effect of treatments on final carcass weight ( P=0.44 ) , with averages of 297kg and 303kg for control and nitrate animals, respectively. The carcass of the control animals had a higher thickness of subcutaneous fat (3mm) in relation to nitrate (2.1mm) ( P=0.08 ). There was a tendency to reduce the emission intensity (g / kg of carcass) by 18% in nitrate animals ( P=0.11 ). There was no difference between the treatments for meat quality and color ( P≥0.32 ) and also in the fatty acid profile ( P≥0.50 ). The use of nitr ate does not provide nitrate residue in meat ( P=0.77 ). It can be concluded that the consumption of nitrate encapsulated by zebu cattle under tropical conditions under pasture grazing at slaughter can alter ruminal parameters, forage consumption and tends t o reduce methane emissions according to forage quality. The consumption of encapsulated nitrate also provides superior slaughter weight, without altering the final carcase weight, and does not alter the quality or leave residue in the meat.
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Palavras-chave
Nitrogênio não proteico, Pasto, Suplemento