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Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system.
Vinyard, J R; Ravelo, A; Sarmikasoglou, E; Monteiro, H F; Arce-Cordero, J A; Johnson, M L; Agustinho, B C; Lobo, R R; Yungmann, M G; Winter, A H R; Gilbertsen, L M; Mills, M N; Soltis, M; Ghizzi, L G; Gusmão, J O; Ferraretto, L F; Faciola, A P.
Afiliação
  • Vinyard JR; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Ravelo A; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Sarmikasoglou E; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Monteiro HF; Department of Animal Sciences, University of Florida, Gainesville 32608; Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis 95616.
  • Arce-Cordero JA; Department of Animal Sciences, University of Florida, Gainesville 32608; Escuela de Zootecnia, Universidad de Costa Rica, San Jose, 11501-2060, Costa Rica.
  • Johnson ML; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Agustinho BC; Department of Animal Sciences, University of Florida, Gainesville 32608; Department of Animal, Veterinary, and Food Sciences, University of Idaho, Moscow 83844.
  • Lobo RR; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Yungmann MG; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Winter AHR; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Gilbertsen LM; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Mills MN; Department of Animal Sciences, University of Florida, Gainesville 32608.
  • Soltis M; Department of Animal Sciences, University of Florida, Gainesville 32608; Department of Animal Science, University of Tennessee, Knoxville 37996.
  • Ghizzi LG; Department of Animal Sciences, University of Florida, Gainesville 32608; Department of Animal Nutrition and Animal Production, University of São Paulo, Pirassununga, 13635-900, Brazil.
  • Gusmão JO; Department of Animal Sciences, University of Florida, Gainesville 32608; Department of Animal Science, Federal University of Lavras, Lavras, 37200-900, Brazil.
  • Ferraretto LF; Department of Animal and Dairy Science, University of Wisconsin-Madison, Madison 53706.
  • Faciola AP; Department of Animal Sciences, University of Florida, Gainesville 32608. Electronic address: afaciola@ufl.edu.
J Dairy Sci ; 106(2): 1002-1012, 2023 Feb.
Article em En | MEDLINE | ID: mdl-36543642
ABSTRACT
The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH3-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH3-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH3-N, or lactate in the effluent samples. Treatment did not affect pH, acetatepropionate ratio, or the concentrations of lactate, NH3-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Propionatos / Lactação Limite: Animals Idioma: En Ano de publicação: 2023 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Propionatos / Lactação Limite: Animals Idioma: En Ano de publicação: 2023 Tipo de documento: Article