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A study was conducted to determine the reliability of the novel in vitro dry matter digestibility (IVDMD) method for predicting the in vivo organic matter digestibility (OMD) of forages. The study was carried out on two sets of feeds of known OMD determined on sheep: set A ( n = 35), consisting of whole crop cereal (corn and barley) herbages and set B ( n = 80), mostly consisting of grass and clover silages. IVDMD was determined by the CEL48-ND method in which 500 mg of dried and ground feed sample was inserted into filter bag (ANKOM Technology Corporation, Fairport, NY, USA) and then the bags were incubated for 48 h at 39 °C in the cellulase solution (celullase Onozuka R10), in the jars of Daisy II Incubator (ANKOM Technology Corporation). After incubation the bags with residues were extracted in a neutral detergent (ND) for 1 h at 100 °C in Ankom 220 Fiber Analyzer (ANKOM Technology Corporation). The data for all sets were used to find the best single and multiple regression equations to predict OMD. For each set the linear regressions were calculated in which OMD was the dependent variable ( Y ) whereas IVDMD determined by CEL48-ND was the predictor X 1 and contents of nutrients (g/kg DM) were predictors X 2 , X 3 , X 4 or X 5 . The equations were compared by means of coefficient of determination ( R 2 ), standard deviation of differences between observed ( Y i ) and predicted value ( Ỹ i ) (residual standard deviation; RSD), and mean square prediction error (MSPE). Additionally, the verification of equations was also done based on the Akaike information criterion (AIC). Mean R 2 for the regression equations of OMD by CEL48-ND was 0.468 (set A), 0.581 (set B) and 0.539 (set A + B). Including the next predictor ( X 2 , X 3 , X 4 or X 5 ) increased R 2 , and decreased RSD, MSPE and AIC, especially in the equations calculated for whole crop corn herbages, grass silages and clover silages. It can be concluded that the in vitro method presented in this study is a simple alternative for existing methods in which buffered rumen fluid is used. Using a standard enzyme available commercially worldwide may decrease variation between laboratories. Further, using filter bags and Daisy Incubator decreases labour costs and use of animals. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of protein source, either soybean meal (SM) or canola meal (CM), and microencapsulated sodium butyrate (MSB) supplementation in a pelleted starter mixture on the development of the gastrointestinal tract (GIT) in dairy calves. Twenty-eight bull calves (8.7 ± 0.8 d of age and 43.0 ± 4.4 kg; mean ± SD) were assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement: CM as a main source of protein without or with MSB or SM without or with MSB. Calves were fed starters ad libitum and exposed to a gradual weaning program, with weaning taking place on 51.7 ± 0.8 d of age. Calves were observed for an additional 3 wk after weaning and slaughtered on d 72.1 ± 0.9 of age, after which the GIT was dissected. Morphometric measurements were recorded, and samples for determination of ruminal fermentation, histology, gene expression, and brush border enzyme activities were collected. Canola meal use in the starter mixture increased abomasal tissue weight, jejunal tissue weight and length, and mRNA expression of SLC16A4 (formerly known as MCT4) and FFAR2 (GPR43) in the ruminal epithelium, and decreased ruminal ammonia and mRNA expression of SLC15A2 (PEPT2) and SLC6A14 (ATB0+) in the proximal small intestine and ileum, respectively. However, MSB inclusion in the starter mixture decreased ruminal papillae length, ruminal epithelial surface, and ruminal epithelium dry weight, while increasing mRNA expression of SLC16A1 (MCT1) in ruminal epithelia. Reduced ruminal surface area associated with MSB supplementation was the most apparent when MSB was combined with CM in the starter mixture. Additionally, MSB supplementation decreased the thickness of omasal epithelium, omasal epithelium living strata, and stratum corneum, and increased duodenal and ileal aminopeptidase A enzymatic activity and ileal aminopeptidase N enzymatic activity. Overall, CM might increase growth of the GIT of calves, particularly of the small intestine, but may negatively affect intestinal epithelium function and peptide and AA absorption. Supplementation of MSB has a negative effect on the ruminal and omasal epithelium development, particularly when combined in a starter mixture with CM. [ABSTRACT FROM AUTHOR]