Energy partition and nitrogen utilization by growing goats fed encapsulated calcium nitrate
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Data
2017-07-03
Autores
Silveira, Raiza Felismino [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O nitrato de cálcio encapsulado (NCE) tem sido estudado nos últimos anos como uma fonte de nitrogênio não proteico (NNP) e representa uma alternativa ao uso do hidrogênio livre no ambiente ruminal, reduzindo assim a emissão de metano e possibilitando uma maior eficiência no uso da energia. Assim, o objetivo do presente estudo foi avaliar o uso do nitrato de cálcio encapsulado como substituto do farelo de soja na partição de energia, oxidação do substrato e síntese de N microbiano. Para isso, doze caprinos machos castrados em crescimento, com peso inicial de 21,95 kg ± 3,19 kg foram usados em um quadrado latino 3 x 3 quadruplicado com três períodos de 48 dias, agrupados pelo peso corporal e distribuídos aleatoriamente em um dos três tratamentos ECN0(SBM) – controle baseado em farelo de soja; ECN1.25 – 1,25% de NCE na matéria seca; ECN2.5 – 2,5% de NCE na matéria seca. Cada período consistia de 21 dias de adaptação, 5 dias de ensaio de metabolismo e 15 dias de mensuração de gases. Entre os períodos foi feito um washout de 7 dias onde todos os animais recebiam a dieta controle. Os dados foram analizados usando o procedimento MIXED do SAS (versão 9.4; SAS Inst., Cary, NC, USA). O modelo usado foi Yjkm: μ + LSi + Periodj + Ani(LS)ki + Treatm + єijkm. Quando significante, o efeito de níveis de NCE foi decomposto em dois contrastes polinomiais ortogonais (linear e quadrático). A significância declarada foi de P < 0,05. As variáveis de produção de calor (PC) e produção de calor em jejum (PCJ) foram covariadas com a ingestão de energia metabolizável. A PC não foi influenciada pelos tratamentos (P > 0,05) e a PCJ mostrou uma redução de aproximadamente 22% (P < 0,05) entre o tratamento ECN0(SBM) e ECN2.5. A emissão de metano reduziu 0,21g pra cada grama de nitrato ingerido. A inclusão de aproximadamente 1% de NCE na material seca resultou em um máximo consumo de energia digestível e metabolizável. Além disso, a PCJ foi menor com a inclusão de NCE mostrando um efeito residual em caprinos em crescimento. Não foi observado efeito significativo na síntese de N microbiano.
Encapsulated calcium nitrate (ECN) has been studied in last years as a source of non-protein nitrogen (NPN) and represents an alternative to use of free hydrogen in the ruminal environment, thus reducing the emission of methane and a higher efficiency in use of energy. Thus the aim of this study was to assess the impact of the use of encapsulated calcium nitrate as a substitute for soybean meal in the energy partition, substrate oxidation, and microbial N synthesis. For this, twelve castrated male growing goats, with initial average weight of 21.95 kg ± 3.19 kg were used in a quadruplicated 3 x 3 Latin square design with three 48-d periods, grouped by body weight (BW) and randomly assigned to three diets: ECN0(SBM) – control based on soybean meal; ECN1.25 - 1.25% of encapsulated calcium nitrate (ECN) on dry matter (DM) basis; ECN2.5 - 2.5% of ECN on DM basis. Each period comprised 21 days for adaptation, five days for metabolism trial (d22 to d26) and 15 days for gas measurements (d27 to d38). Between periods, a washout period was provided for 7 d during which the control diet was fed. The data were analyzed using MIXED procedure of SAS (version 9.4; SAS Inst., Cary, NC, USA). The model used for each treatment was the following: Yjkm: μ + LSi + Periodj + Ani(LS)ki + Treatm + єijkm. When significant, the effect of levels of ECN was decomposed into two orthogonal polynomial contrasts (linear and quadratic). Significance was declared at P < 0.05. The heat production (HP) and fast heat production (FHP) were covariated with the metabolizable energy intake. The HP was not influenced by treatments (P > 0.05) and FHP showed a reduction of approximately 22% (P < 0.05) between ECN0(SBM) and ECN2.5. The emission of methane reduced 0.21 g for each g of nitrate intake. The inclusion of approximately 1% of ECN on DM results in a maximum DE and ME intake. Also the FHP is lower with ECN inclusion showing a residual effect on growing goats. No effect is observed in MicN synthesis.
Encapsulated calcium nitrate (ECN) has been studied in last years as a source of non-protein nitrogen (NPN) and represents an alternative to use of free hydrogen in the ruminal environment, thus reducing the emission of methane and a higher efficiency in use of energy. Thus the aim of this study was to assess the impact of the use of encapsulated calcium nitrate as a substitute for soybean meal in the energy partition, substrate oxidation, and microbial N synthesis. For this, twelve castrated male growing goats, with initial average weight of 21.95 kg ± 3.19 kg were used in a quadruplicated 3 x 3 Latin square design with three 48-d periods, grouped by body weight (BW) and randomly assigned to three diets: ECN0(SBM) – control based on soybean meal; ECN1.25 - 1.25% of encapsulated calcium nitrate (ECN) on dry matter (DM) basis; ECN2.5 - 2.5% of ECN on DM basis. Each period comprised 21 days for adaptation, five days for metabolism trial (d22 to d26) and 15 days for gas measurements (d27 to d38). Between periods, a washout period was provided for 7 d during which the control diet was fed. The data were analyzed using MIXED procedure of SAS (version 9.4; SAS Inst., Cary, NC, USA). The model used for each treatment was the following: Yjkm: μ + LSi + Periodj + Ani(LS)ki + Treatm + єijkm. When significant, the effect of levels of ECN was decomposed into two orthogonal polynomial contrasts (linear and quadratic). Significance was declared at P < 0.05. The heat production (HP) and fast heat production (FHP) were covariated with the metabolizable energy intake. The HP was not influenced by treatments (P > 0.05) and FHP showed a reduction of approximately 22% (P < 0.05) between ECN0(SBM) and ECN2.5. The emission of methane reduced 0.21 g for each g of nitrate intake. The inclusion of approximately 1% of ECN on DM results in a maximum DE and ME intake. Also the FHP is lower with ECN inclusion showing a residual effect on growing goats. No effect is observed in MicN synthesis.
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Palavras-chave
Calorimetria indireta, Digestibilidade, Gases de efeito estufa, Respirometria, Digestibility, Greenhouse gas, Indirect calorimetry, Respirometry