Determination of the energy content of forage materials through the relationship between the in vitrogas production technique and the mechanistic equation of the NRC (2001).
The objective of this study was to estimate the metabolizable energy (ME) of different forage sources used in Costa Rica through the NRC equation (2001) and the equations used in the in vitro gas production methodology at 24 hours of incubation (PG24h). The chemical, bromatological composition and gas production were analyzed at the Animal Nutrition Research Center (CINA). The two equations with the best Pearson correlation coefficients with respect to the NRC (2001) were selected : that of Steingass and Menke (1980) and that of Menke and Steingass (1988). The relationship between the nutritional composition of the feedstuffs and both energy estimation methods was analyzed with Pearson analysis correlation and linear regression. The forages with the highest and lowest metabolizable energy obtained from the NRC methodology (2001) were Ryegrass (2.59 Mcal kg/DM) and Cameroon (1.79 Mcal kg/DM). According to the NRC equation (2001), it was determined that neutral detergent fiber (FDN), acid detergent fiber (FDA) and lignin negatively influence the energy concentration (R2 = -0.56; -0.54; - 0.35; p <0.05, respectively), while crude protein (PC) and ether extract (EE) have a positive correlation. The equation with the highest determination coefficient (R2 = 0.72) considers the variables of PG24h, PC, FDN and lignin. Gas production is not affected by the concentration of PC, ash and EE (p <0.05), but it is negatively affected by the FDN, FDA and lignin, with a Pearson correlation coefficient of -0.44, -0.32 and -0.33 (p <0.05), respectively. The forage with the highest PG24h was sugar cane, followed by Festulolium and Ryegrass, while Cameroon and Cratylia grass obtained lower values. Ryegrass and Cameroon were the forages with the highest and lowest energy, respectively, estimated from the selected gas equation. The fibrous fractions were negatively correlated with the energy determined by the selected gas equation, while the PC and EE present a positive relationship. The gas production technique proved to be effective in estimating the energy content of forage sources, based on a methodology that includes less analysis and therefore results in a lower cost for laboratory analysis.
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Universidad de Costa Rica
2020
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| Online Access: | https://revistas.ucr.ac.cr/index.php/nutrianimal/article/view/41475 |
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