In ca�le, energy-rich feeding causes an increase in the size of rumen papillae and leads to considerable mucosa proliferation (Dirksen et al., 1984). In animals fed low and high energy diets rumen mucosa revealed progressive reduction and intensive proliferation, respectively (Dirksen et al., 1985). Intensity of rumen fermentation increases with the increasing intake of concentrate and simultaneously the occurring volatile fa�y acids promote the structural development of the rumen epithelium (Kauffold et al., 1977;Hofmann and Schnorr, 1982;Zitnan et al., 1998).So far, insufficient or no investigations at all have been carried out into the effects of the diet upon the development of small intestinal mucosa.According to Tivey and Smith (1989), changes in the development of enterocytes and in the structure of villi determine the digestive and absorptive capacity of the small intestine. Kreikemeier et al. (1990) studied the activity of carbohydrate digesting enzymes in Holstein and Longhorn bulls and observed it to be influenced by the type of diet and the level of feed intake. Mir et al. (1997) considered the length of villi and crypts and mucosal carbohydrase activity to be an important factor in nutrient absorption; they recorded differences in these parameters between different cattle breeds, of which Holstein bulls had the highest lactase activity and the longest villi in the middle part of the intestine. ABSTRACT: This study examined the effects of extensive and intensive feeding on the morphology of the gastrointestinal tract as well as on the level of carbohydrase activity in the small intestine of growing ca�le. Fourteen growing male bulls aged 5 months were divided into two feeding groups. The extensively fed animals were kept on pasture in the summer and in a stall in the winter whereas the intensively fed group was housed all the year long. The bulls were slaughtered 16 h a�er the last feeding at the age of 18 months. Rumen fluid samples and mucosa samples from the ventral ruminal sac and the intestinal tract (duodenum, jejunum, ileum) were subjected to analyses. Evaluation of rumen fermentation did not reveal significant differences between the groups, however, the molar proportions of propionic acid were increased in the intensively reared bulls. As to the activity of the individual carbohydrase enzymes (maltase, cellobiase, lactase) no significant differences could be stated between the groups. Comparison to the extensively reared group revealed that the length and width of papillae of the ventral ruminal sac was significantly increased in the intensively reared animals (P < 0.001) and so was the papillar surface per cm 2 of mucosa (P < 0.001). The length of duodenal villi in the intensive group was singnificantly increased (P = 0.026) whereas that of the jejuenal villi approached the limits of significance (P = 0.052) when compared to the extensive group. There were no significant differences in the depth of crypts, however, the crypts of the intensively reared animals were somewhat deeper. The lengt...

The effect of plant oils and aspartate (ASP) on rumen fermentation in vitro. The objective of this study was to determine the effect of plant oils (rapeseed - RO, sunflower - SO; linseed - LO; 10% wt/wt) and 8 mmol sodium aspartate on rumen fermentation of a diet (250 mg) consisting of hay, barley and sugar beet molasses (60 : 30 : 10). Rumen fluid was collected from two Slovak Merino sheep fed the same diet twice daily. Mixed ruminal micro-organisms were incubated in fermentation fluid (40 ml) containing rumen fluid and McDougall's buffer (1 : 4). Incubations were carried out in batch cultures for 72 h at 39 degrees C two times in a 3-week intervals. When compared to the control, all supplemented diets (RO, SO, LO, ASP) significantly increased the pH, the mol% of propionate (LO + 8.7%; SO + 10.12%; RO + 8.65%; ASP + 5.86%) and the acetate : propionate ratio and numerically decreased methane production (SO -32.8%; LO, RO -30.08%; ASP -21.56%). Lactate production was also significantly decreased. Addition of plant oils to aspartate-treated incubations partly inhibited the decrease of n-butyrate, lactate and the increase of pH and in vitro dry matter digestibility (IVDMD) caused by ASP treatment. The effect of combined additives (RO + ASP, SO + ASP, LO + ASP) on methane production SO + ASP (-19.23%) and mol% propionate SO + ASP (+2.66%), LO + ASP (+4.28%) was less effective. All combined additives caused a significant decrease in digestibility of the given feeds. No effect of plant oils and ASP could be observed on the parameters of rumen fermentation (mainly methane and propionate).

Several methods were used for the evaluation of feed protein for rumen degradability and intestinal digestibility of rumen undegraded protein (RUP). The aim of this work was to explore the possibility of using the Cornell method of predicting the fraction RUP. An in situ method was adopted for estimation of degradability parameters (a, b, c) and effective degradable crude protein (EDCP), and five nitrogen fractions (A, B 1 , B 2 , B 3 , and C) were determined according to the Cornell Net Carbohydrate and Protein System (CNCPS). Fifty-one feedstuffs -13 cereals grains, 5 legume seeds, 3 oilseeds, 11 oilseed by-products, 4 distillers dried grains with solubles (DDGS), and 15 silages (maize, lucerne, grass, and grass-clover) -were used in this work. The examined feedstuffs varied widely in nutrient composition. Fraction B 1 (soluble true protein) in forages was small (2.5-5.7% of total N), but it varied to a large extent in concentrates (DDGS 0.9-1.2, legumes 46.5-63.7, oilseeds meal 17.1-51.8% of total N). Fraction B 2 represented a large proportion of the total protein in oil seed meals (44.3-82.6% of total N) and in DDGS (55.8-77.8% of total N), too. Fraction B 3 was relatively small (less than 10% of total N) in all feedstuffs and declined with increasing acid detergent insoluble nitrogen (ADIN) concentration. The concentration of ADIN fraction in feeds affected ruminal degradability. Lucerne silage, with a high content of ADIN (30.9% of total N), had a low effective crude protein (CP) degradability (57%). Correlation between EDCP and fraction A was r = 0.76. A weaker correlation (r = 0.67) was found between in situ parameter "b" and fractions B 2 and B 3 (r = 0.59), respectively. The results show that much more samples of all feed types should be analyzed to obtain results allowing a more exact prediction of CP degradability and RUP.

An experiment was conducted to evaluate the effect of pea-based diet fed to growing and finishing pigs on performance, carcass and meat quality. Thirty pigs (Slovak White Meaty or crossbred Slovak White Meaty × Pietrain) were tested for the malignant hyperthermia (MH) syndrome using a DNA based test. Pigs were allotted to control and experimental groups (of 10 pigs each, equal for normal -NN and heterozygotes -Nn and equal for barrows and gilts) with 2 pigs per pen. Pigs receiving the control treatment were fed soybean meal diets. In all diets fed to experimental pigs the soybean meal was replaced by 30% of raw or extruded pea-based meal balanced on an isonitrogenous and isoenergetic level. Pig performance was monitored for the entire experimental period. At the conclusion of the experiment, carcass and meat quality were measured. The results did not show any effects of dietary treatments on average daily gain (P > 0.05). The evaluation of carcass composition showed no significant differences (P > 0.05) in backfat and lean percentage values between the control and experimental pigs. Chemical composition (total water, protein, intramuscular fat) and fatty acid profile did not differ among treatments (P > 0.05). The differences in the omega-6/omega-3 ratio were significant (P > 0.05) between animals fed the control ration with soybean meal and animals receiving the pea ration. No differences were observed between control and experimental pigs in pH (45 min and 24 h), colour (24 h), drip loss (24 h) and tenderness (5 day) measured with Warner-Bratzler instrument (P > 0.05). In conclusion, peas may replace the soybean meal in diets fed to growing and finishing pigs without negative influence on pig performance, carcass composition and meat quality.

This study was conducted to investigate changes in in vitro dry matter digestibility (IVDMD), volatile fatty acids (VFA) production and cell-wall constituent degradation in wheat straw treated with six white-rot fungi: Daedalea quercina, Hericium clathroides, Phelinus laevigatus, lnonotus andersonii, lnonotus obliquus, and lnonotus dryophilus. The incubation of wheat straw for 30 days at 28°C improved IVDMD from 41.4 (control) to 59.2% for D. quercina, 56.3% for H. clathroides, 50.2% for P. laevigatus, 51.4% for 1L andersonii, 52% for 1L obliquus, and 55.9% for 1L dryophilus. In contrast, the growth of fungi was accompanied by the dry matter loss of wheat straw: 43% for D. quercina, 12% for H. clathroides, and 22-25% for the other fungi. It is evident that the increase in digestibility by D. quercina was not offset by a loss of dry matter. The total VFA production during the rumen fermentation of fungus-treated straw was slightly increased by H. clathroides and 1L dryophilus only. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were reduced in fungus-treated straw. Out of the three fractions (hemicellulose, cellulose, and lignin), hemicellulose and lignin showed the largest proportionate loss after inoculation with the fungi D. quercina, H. clathroides, P. laevigatus, and 1L obliquus. The other two fungi showed the largest proportionate loss in cellulose and hemicellulose contents. The results of this study suggest that the digestion enhancement of wheat straw colonized by white-rot fungi is regulated by complex factors including the degradation of structural carbohydrates and lignin.