N-free Extract Research Articles

Effect of xylanase supplementation to cereal-based diets on apparent fecal digestibility and growth performance of pigs / Wpływ suplementacji diet z udziałem zbóż ksylanazą na pozorną strawność kałową i wskaźniki tuczu świń

Abstract A total of 300 growing-finishing pigs (30-110 kg BW), the offspring of Naima sows and Duroc boars, were allocated to three dietary treatments (five pens per treatment, 10 males and 10 females per pen). The growth performance of pigs was determined, and the apparent digestibility of nutrients and energy in animals fed grower diets was calculated by the simple balance method. Complete diets with a high content of triticale (70%-73%) and barley (6.8%-12%) were supplemented with endo-1,4-beta-xylanase (6200 EPU per g). The minimum xylanase activity per kg feed was 1050 and 1500 EPU. Xylanase, at activity levels of 1050 and 1500 EPU kg-1 complete diet, significantly (P≤0.05) increased the apparent digestibility of total protein and highly significantly (P≤0.01) that of crude fat. No significant differences in the digestibility of N-free extractives and energy were found between groups. The increased activity of xylanase (1500 EPU kg-1 feed) contributed to an increase in the digestibility of dry matter, crude fibre (P≤0.05) and organic matter (P≤0.01), compared with the control group. Higher (P≤0.01) daily gains and average final body weights were noted in pigs fed diets supplemented with the mono-enzyme preparation. The feed conversion ratio (FCR) tended to improve in pigs receiving xylanase-supplemented diets, but the observed differences were statistically non-significant.

SEASONAL PRODUCTIVITY AND COSTS PRODUCTION OF DUNALIELLA BARDAWIL UNDER EGYPTIAN CONDITIONS

Microalgae are the natural feeds of many aquaculture species and are the basis of the natural food. This work aimed at the investigation of the possibility cultivation green algae Dunaliella bardawil under outdoor conditions (Egyptian conditions) was studied, variation in chemical composition of algal cells due to season of cultivation was also investigated and costs production. Average cell mass productivity reached the maximum in summer followed by autumn and spring. The algae were grown in batches using successively larger containers, the yield of the biomass, initial (1.5x106 cells/ml) and final density (12 x106 cells/ml)of Dunalilla bardawil were obtained at four days culture 96 hours. Methods of drying significantly affected amino acid composition. Growth and chemical composition of Dunalilla bardawil cells are maximum crude protein content was around 52% for all seasons. Amino acid composition showed no significant difference between the batch cultures. Methionine was the limiting amino acid. The calculated average and maximum productivity of algal cells and crude protein showed the highest value in summer culture followed by autumn and spring seasons. The chemical composition of the algal powder was similar for all batches in percent of dry weight, 51.8 % crude protein(C.P), 8.9 % ether extract (E.E), 6.5 % crude fiber (C.F), 9.2% (ash), 23.6% N. free extract (NFE),and algal extracts containing antioxidant vitamins. The high cost of labor in the outdoor cultivation which represents approximately 49.26 % from the total operating costs, followed by the nutrients, which recorded about 26.10 % from the total costs, while the electricity had minimum cost recorded about 24.63 % from the total costs. The harvesting of ton lives algae and oven dried gave 950 g dry biomass. The 1.052 ton live algae produced 1kg dry biomass. The costs of Ingredient outdoor culture for producing live Dunalilla bardawil and operating dry biomass were about 15.30 Pound ton of live algae and the costs of dry weight were LE 20.30 Pound, while operating costs were LE 21.37 Pound/kg dry biomass.

Effect of β-mannanase on the digestibility of diets with different protein sources in dogs determined by different methodologies1

This experiment aimed at evaluating the effects of including the enzyme, β-mannanase, in dog (Canis lupus familiaris) diets based on either poultry (Gallus gallus domesticus) by-product meal (PBM) or soybean [Glycine max (L.) Merr.] Meal (SBM). The second objective was to evaluate 3 methods for determining energy and nutrient digestibility values in diets fed to dogs: total fecal collection (TFC) and use of aia or crude fiber (CF) as a marker. Eight dogs were allotted to a replicated latin square (4 by 4) design. There were 2 diets based on PBM as the major protein source and 2 diets based on SBM as the major protein source. Within each protein source, 1 diet contained no β-mannanase and 1 diet contained 0.01% β-mannanase. Diets were fed for an adaptation period of 5 d followed by 5 d of TFC. Fecal score (1 = watery feces to 5 = dry, hard pellets), pH, DM, and fecal volume were determined. The apparent total tract digestibility (ATTD) of DM, OM, CP, ether extract (EE), N-free extract (NFE), and GE, and ME content were calculated using the methods of TFC, AIA, and CF. Data were analyzed as a 2 by 2 by 3 split-split-plot design (β-mannanase, protein source, and digestibility calculation procedure). There were interactions between protein source and β-mannanase (P < 0.05). Supplementation of β-mannanase increased ATTD of nutrients and energy and ME (+ 195.3 kcal/kg) and also reduced fecal production in the diet with SBM, but not in the diet that contained PBM. There was an interaction between digestibility calculation procedure and protein source (P < 0.05). The use of AIA overestimated ATTD of the diets containing PBM, but digestibility values estimated based on TFC and CF were not different. Dogs fed diets containing SBM produced more feces with greater moisture content and lower pH compared with dogs fed the PBM diet (P < 0.05). Addition of 0.01% β-mannanase increased (P < 0.05) the digestibility and ME content of the diets containing SBM, but did not improve (P > 0.05) fecal texture. Results indicated that values for ATTD of energy and nutrients in diets containing sbm are not different if they are calculated based on TFC, AIA, or CF, but use of AIA may result in an overestimation of values for ATTD of energy and nutrients in diets containing PBM.

Water content of faeces is higher in the afternoon than in the morning in morning-fed dogs fed diets containing texturised vegetable protein from soya

Faecal moisture content can determine whether faeces appear soft or firm, and faecal character can influence whether owners are satisfied with a dog food. In a previous study, dogs appeared to produce softer faeces after noon. The purpose of the present study was to determine whether time of defecation affected canine faecal water content. A total of eight hound dogs were fed one of four canned diets as a single meal each morning for 1 week per diet in a Latin square design. All four diets contained approximately 77 % moisture and, on a DM basis, 24 MJ/kg gross energy, 23 % crude protein, 32 % crude fat, 31 % N-free extract and 1 % crude fibre. The proportion of dietary protein from soya-derived texturised vegetable protein (TVP):beef was 0:100, 14:86, 29:71 and 57:43, respectively. Soya carbohydrate partially replaced maize starch as TVP increased. Faeces were collected by direct catch during the sixth morning and afternoon of each diet period. Mean faecal moisture content was greater in the afternoon than in the morning (79 v. 71 %; P = 0.01) and increased with dietary TVP (P ≤ 0.0001), and there was an interaction between time of day and percentage TVP (P = 0.003). Faecal moisture content differed from morning to afternoon only with TVP in the diet. Faecal wet weight was similar from morning to afternoon. This suggests that time of day and presence of TVP from soya should be taken into account when evaluating the effect of a diet on faecal form and moisture content in dogs fed once daily.

Estimation of the dietary nutrient profile of free-roaming feral cats: possible implications for nutrition of domestic cats

Cats are strict carnivores and in the wild rely on a diet solely based on animal tissues to meet their specific and unique nutritional requirements. Although the feeding ecology of cats in the wild has been well documented in the literature, there is no information on the precise nutrient profile to which the cat's metabolism has adapted. The present study aimed to derive the dietary nutrient profile of free-living cats. Studies reporting the feeding habits of cats in the wild were reviewed and data on the nutrient composition of the consumed prey items obtained from the literature. Fifty-five studies reported feeding strategy data of cats in the wild. After specific exclusion criteria, twenty-seven studies were used to derive thirty individual dietary nutrient profiles. The results show that feral cats are obligatory carnivores, with their daily energy intake from crude protein being 52 %, from crude fat 46 % and from N-free extract only 2 %. Minerals and trace elements are consumed in relatively high concentrations compared with recommended allowances determined using empirical methods. The calculated nutrient profile may be considered the nutrient intake to which the cat's metabolic system has adapted. The present study provides insight into the nutritive, as well as possible non-nutritive aspects of a natural diet of whole prey for cats and provides novel ways to further improve feline diets to increase health and longevity.

냉풍건조 곶감과 천일건조 곶감의 이화학적 품질특성

This study was performed to investigate physicochemical properties of cold-air dried persimmon and traditional dried persimmons. Moisture contents and water activity were lower at cold-air dried persimmon than traditional persimmons. Crude protein and crude fat were not significant differences, Crude ash and N-free extracts of cold-air dried persimmon were, relatively, high as comparing to the traditional dried persimmons. Brix in cold-air dried persimmon was the highest. In the hunter's color values, L, a and b values of cold-air dried persimmon were lowed than traditional dried persimmons. There was not significant differences at the texture of semi-dried persimmons, but cold -air dried persimmon were relatively high than the traditional dried persimmons in hardness, gumminess, chewiness. Free sugars contents were only glucose and fructose in an sample. Free amino acids contents were seventeen sorts, glutamic acid and alanine were high in order of contents.

Fibre analysis and fibre digestibility in pet foods – a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre*

Six dry dog foods and six dry cat foods with different carbohydrate sources were investigated in digestion trials. Food and faecal samples were analysed for CF, TDF and starch. In dogs, also neutral detergent fibre (aNDFom) and acid detergent fibre (ADFom) were analysed. N-free extract (NfE) was calculated for CF, and similarly for all other fibre analyses. Linear regressions were calculated between fibre intake and faecal fibre excretion. True digestibility was calculated from the regression coefficients [true digestibility in % = (1 - regression coefficient)*100], with the intercept of the equation representing excretion of material of non-food origin. Crude fibre analyses gave the lowest values, and TDF the highest, while ADFom and aNDFom were in between. Variation between diets was lowest in CF and highest in TDF. Total dietary fibre, aNDFom and ADFom in food were positively correlated. Crude fibre in food did not correlate with any other method. The NfE analogue for TDF was closest to the starch content. Methods of fibre analyses in faeces did not agree very well with each other. Crude fibre had the lowest apparent digestibility, followed by ADFom, TDF and aNDFom. For all fibre analyses, there was a significant correlation between fibre intake and faecal fibre excretion. True digestibility was close to zero for CF, with a high uniformity in both species. In dogs, true digestibility of aNDFom was 53%, of ADFom 26% and of TDF 37%; in cats, true digestibility of TDF was 31%. Except for CF, the intercept of the regression equations suggest that faecal excretion of some material of non-food origin is analysed as fibre. A combination of TDF and CF analyses might give good information on the content of total (TDF), unfermentable (CF) and partially fermentable fibre (TDF-CF) in pet foods.

Chemical Composition and Nutritive Value of Protein of the Pea Seeds - Effect of Harvesting Year and Variety

Chemical Composition and Nutritive Value of Protein of the Pea Seeds - Effect of Harvesting Year and Variety We tested nutritional usability of pea seeds (Pisum sativum L.) at full maturity. Four white-flowering and 5 colour-flowering new Polish cultivars were compared. We determined proximate composition of ground seeds collected over 4 years period as well as amino acids, minerals (Ca, P, Na, K), tannins and fiber fractions (NDF, ADF, ADL). The seeds contained between 224 and 260 g·kg-1 of crude protein which was rich in Lys (6.8±0.8 g) but poor in Met+Cys (2.0±0.2 g·16 g-1 N). The amount of tannins (as tannic acid equivalent) in white-flowering cvs was 4.3±0.9 g and in colour-flowering - 7.4±2.2 g. The calculated protein nutritional values were compared against amino acid standards of human and animal nutrition and the whole egg protein. Effects of the cropping year and variety variance in respect of chemical composition of seeds were examined. Crude protein, crude oil, N-free extractives, tannins, K, amino acid content: Leu, Phe+Tyr and Ala content were influenced significantly by the cultivar, while the cropping year had a significant influence on dry matter, crude ash, crude protein, crude fibre, crude oil, N-free extractives ADF and ADL fiber fractions, content of P, Na and K, most of the amino acid levels and on nutritional values of the protein measured by means of CS and EAAI indices.

Skład chemiczny i jakość kiszonek z sorgo cukrowego i kukurydzy

Sweet sorghum (Sorghum saccharatum) silage, maize (Zea mays) silage, and sorghum and maize (1:1) silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88%) in sorghum silage and the highest (37.45%) in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre and acid detergent fibre were the highest in sorghum silage and the lowest in maize silage. The silages were dominated by lactic acid, with trace amounts of butyric acid. Maize silage was higher lactic acid and higher total acids than others. All silages were of very good quality according to Flieg-Zimmer scale. Silage pH ranged from 4.20 to 4.31. Sorghum silage was characterized by higher aerobic stability (81h) compared to the other silages from maize (74h) and sorghum and maize 1:1 (69h).

Changes of chemical composition and nutritive values of Reed Canary Grass (Phalaroides arundinacea) in first growth

Change in chemical composition and nutritive value of Reed Canary Grass (Phalaroides arundinacea) were investigated in springtime in 2004-2006. The nutritive value of Reed Canary Grass was observed between the end of April and the middle of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy maintenance, Metabolizable Protein Energy dependent,Metabolizable Protein N-dependent.It was also analysed whether a relationship between the climatic factors affecting the growing period as well the chemical composition of grasses and the annual weather were looked for. For the estimation of weather conditions the climate index was calculated. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. Between 2004 and 2006, the result of the analysis of nutritive value indicated a significant difference with respect to each chemical composition at the rate of P&lt;0.01 depending on the time when the samples were taken. According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing endency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance revealed an alteration only in the first half of the observed period. The same alteration tendency can be detectedin the Net-Energy growth.

The development of a metabolizable energy system for horses

The development of a metabolizable energy (ME) system for horses is described. Predictive equations for gross energy and digestible energy (DE) are revisited. The relationship between feed protein content and renal energy losses and the relationship between feed fibre content and methane energy losses were analysed in a literature review to develop predictive equations for ME. In horses, renal energy losses are much higher than losses by methane energy. Renal energy losses were correlated more strictly to protein intake than to digestible protein intake. The reason probably is that per gram of digestible crude protein energy losses are higher for roughage than for concentrates presumably because phenolic acids of forage cell walls contribute to higher urinary energy losses. However, digestibility of protein is lower in forages than in concentrates. The net result is a rather constant urinary energy loss of 0.008 MJ/g of crude protein in the feed. Methane losses in horses are smaller than in ruminants, presumably because of reductive acidogenesis in hind gut fermentation. Methane energy losses in equines are closely related to crude fibre intake. The mean methane energy losses amount to 0.002 MJ ME/g of crude fibre which can be used to correct for methane losses. Both corrections can be made for any predictive equation for DE. Metabolizable energy is then calculated as follows: ME MJ/kg = DE MJ/kg - 0.008 MJ/g crude protein - 0.002 MJ/g crude fibre. The equation of Zeyner and Kienzle (2002) to predict DE was adapted as mentioned above to predict ME: ME (MJ/kg dry matter) = -3.54 + 0.0129 crude protein+0.0420 crude fat-0.0019 crude fibre+0.0185 N-free extract (crude nutrients in g/kg dry matter).

ORIGINAL ARTICLE: High calcium intake differentially inhibits nutrient and energy digestibility in two different breeds of growing dogs

The current study was part of a larger investigation of two breeds of growing dogs (Dobenecker, 2002). The apparent digestibility of protein, fat, nitrogen-free extract (N-free extract) and organic matter as well as energy of a tripe and rice-based diet supplemented either with normal calcium [~1.1% dry matter (DM), normal calcium (NC)] or excess calcium [~3.6% DM, high calcium (HC)] was determined in two breeds of growing dogs of different sizes, including 30 Beagles and 44 Foxhound-Boxer-Ingelheim Labrador crossbred dogs (FBIs), at the ages of 12, 18 and 24 weeks. Apparent energy digestibility was significantly impaired by excess of calcium in both dog breeds, and the effect was stronger in FBIs than in Beagles (NC vs. HC in FBIs: 88.3 ± 2.6% vs. 84.7 ± 3.7%; NC vs. HC in Beagles: 89.0 ± 2.4% vs. 86.6 ± 3.4%; p < 0.05 in both FBIs and Beagles). The same was true for organic matter, N-free extract, crude protein and fat. The decrease in protein and fat digestibility was significant in FBIs, but not in Beagles. By contrast, the apparent digestibility of ash was lower in FBIs than in Beagles. Taken together, the results of the current study suggest that excess dietary calcium may be associated with systematic differences in nutrient digestibility by different breeds of dogs.

Nutritive value of Timothy (Phleum pratense L.) during primary growth in 2005

In this paper we analysed the change of the chemical composition and nutritive value of Timothy observed during the spring of 2005. The nutritive value of Timothy was observed between the end of April and the beginning of June relating to the following parameters: crude protein, crude fibre, crude fat, ash, N-free extract, net-energy growth, net-energy lactation, net-energy maintenance, Metabolizable Protein Energy dependent, Metabolizable Protein N-dependent. We also analysed whether a relationship between the environmental factors that affect thegrowing period of grasses and the chemical composition can be detected or not. While testing for correlation, the number of days from 1st January, the amount of heat accumulation, solar radiation and rainfall were considered as independent coefficients.For the estimation of weather conditions we calculated the climate index. The observed year can be described as a year with a rainfall above the average and abundant solar radiation. A correlation can be detected between the change of parameters of nutritive value and the quality of the current year. In 2005 the result of the analysis of nutritive value was showed a significance difference with respect to each chemical composition at the rate of P&lt;0.001 depending on the time when the samples were taken.According to the outlined data it can be stated that the change of the value of crude protein and ash show decreasing tendency agreeing the research literature. In parallel with the change of nutritive value, the amount of crude fibre and N-free extract increased. However, the value of Net-Energy maintenance showed an alteration only in the first half of the observed period. The same alteration tendency can be detected in the Net-Energy growth and the Net-Energy lactation.

Influence of dietary nitrogen sources with different ruminal degradability on growth performance of Comisana ewe lambs

The effect of diets with different ruminal degradability on growth performance of Comisana ewe lambs was studied. Forty-five ewe lambs, with average live weight of 16 ± 0.55 kg (mean ± sem), were allocated randomly to three isocaloric (2.19 Mcal/kg), isonitrogenous (15.5% of crude protein) diets for 18 weeks. Pelleted total mixed rations (PTMR) were formulated in order to provide N sources with different ruminal degradability: (1) urea (46% N) associated to soybean meal (high-degradability diet, HD), (2) soybean meal (medium-degradability diet, MD) and (3) corn gluten meal associated to soybean meal (low-degradability diet, LD). In vivo nutrient apparent digestibility of the three PTMR was determined using Comisana rams (mean LW 68 ± 3.8 kg) and indicated significant ( P < 0.05) differences for protein, ether extract, N-free extract, neutral detergent fiber (NDF) and hemicellulose fractions. The results from the current trial using Comisana ewe lambs showed that average daily gain was unaffected by ruminally degradable protein and ruminally undegradable protein ratio in diets ( P > 0.05). Final body weight in ewe lambs fed the MD diet was significantly greater ( P < 0.05) compared with the HD and LD treatment groups. Feed conversion ratio was lower in MD diet than HD and LD diets ( P < 0.05).

Effect of enzyme supplementation of diets based on maize or hominy feed on performance and nutrient digestibility in broilers

Two experiments were conducted to determine the nutritional value of hominy feed and impact of an enzyme preparation in broiler chickens diets. In the fi rst experiment, 480 one-day-old chickens were fed 6 experimental diets (treatments) from the day of hatching to 35 days of age with increasing quantities of hominy feed replacing 0, 50 and 100% of maize. The diets were fed with or without enzyme supplementation. Each treatment consisted of 10 replications, 8 birds per replication. During the entire period, chickens from the group receiving maize had a lower (P<0.05) feed conversion ratio (FCR) in comparison with other experimental groups. Body weight gains were also reduced (P<0.05) when maize was substituted by hominy feed. Addition of enzymes improved FCR (P<0.05). Experiment two was carried out using 120, 21-day-old Ross male chickens in 10 treatments, 12 birds per experimental group. Birds fed maize hominy diets had the lowest organic dry matter and N-free extractives apparent digestibility coeffi cient (P<0.05). Hominy diets also had a lower AME N value (P<0.05). Enzyme addition improved the apparent digestibility of all nutrients (P<0.05) except crude fat.

Effect of high rape cake content supplemented in enzymes on the nutritional value of a broiler diet and intestinal lactic acid bacteria number

The studies were designed to determine an effect of partial replacement of soybean meal with rape cake supplemented with enzymes on the nutritional value of diets and the number of lactic acid bacteria (LAB) in the ileum and caecum of broilers. The experiment 1 (growth trial) was carried out on 120 one-day-old broiler chickens Ross 308 which were randomly divided into four homogenous groups, 30 birds per group (15 males and 15 females). Each treatment consisted of six replicates of 5 birds. A control diet contained soybean meal whereas in the experimental, a part of the soybean meal was replaced by 15% rape cake from the Kaszub cultivar and supplemented with enzyme preparations containing xylanase or phytase added individually or in combination. On the 21st day of experiment six birds from each group were scarified and the ileum and caeca were isolated for lactic acid bacteria (LAB) determination. The experiment 2 (digestibility trial) was carried out on 60 sevenday-old chickens divided into four treatments of 20 birds (4 replications of 5 birds) to determine nutrient digestibility of diets used in the growth trial. The digestibility test was carried out by the total collection method. The inclusion of 15 % rape cake instead of soybean meal and the addition of enzyme preparations did not decrease body weight gain and feed intake. The feed conversion ratio (FCR) was higher in the group fed the diet in which phytase was added separately. A simultaneous application of xylanase and phytase statistically (P<0.05) increased the digestibility of crude fibre and N-free extracts. The lactic acid bacteria number was the highest in the caecum and ileum of birds fed the diet containing the xylanase preparation, whereas xylanase and phytase preparations added in combination had no effect on lactic acid bacteria number.

Appraisal of ingestion and digestibility in growing rabbits using near infrared reflectance spectroscopy (NIRS) of feeds and faeces

The aim of this work was to examine whether faecal profiling using NIRS could be profitable for promote the Best Available Techniques (BAT) in the rational feeding of rabbits. A set of 51 feed samples, taken from 12 experimental diets, and of 66 dried grouped faeces samples, belonging to four nutrition experiments, with 130 ad libitum registered feed intakes (CV=25%), were submitted to a UV-Vis-NIRS scan (350-2500 nm) in order to calibrate the chemical composition and nutritional parameters, the ingestion aptitude and digestibility. A chemometric system has made it possible to contemporary use the spectrum of the input diet concatenated together with the spectra of the related output pool of the dried faeces. The daily measured feed intake, in absolute or in relative terms as ingestion per unit of metabolic weight, obtained a good resolution for the spectra of the feeds (R2cv=0.80 and 0.75, respectively), for the faeces (0.81 and 0.80) and for the joint evaluation of the concatenated spectra (0.87 and 0.81). The intake was positively correlated to the mineral, insoluble ash, protein, gross energy, crude fiber and acid detergent fiber (ADF) content in the feeds, and negatively correlated to the N-free extract, lignocellulose and all the digestibility coefficients, except crude fiber. Very significant improvements, on average equal to 0.20 R2 points, were also provided to the digestibility coefficients when using the concatenated method; in decreasing order: neutral detergent fiber (R2cv=0.00, 0.18 and 0.50 for the feeds, faeces and concatenated, respectively), ADF (0.00, 0.45 and 0.62), ether extract (0.53, 0.52 and 0.86), crude protein (0.53; 0.53 and 0.75), and gross energy (0.61; 0.74 and 0.83). The results corroborate previous knowledge and show the possibility of using NIRS faecal profiling in rabbit nutrition, which together with the NIRS of the feeds, could contribute to nitrogen monitoring.

Morphology of small intestinal mucosa and intestinal weight change with metabolic type of cattle

The objective of this study was to investigate rumen fermentation, apparent digestibility of nutrients, and morphology of ruminal und intestinal mucosa in two cattle breeds of different metabolic type. From each breed six purebred German Holstein (H) bulls representing the secretion type and six Charolais (CH) bulls representing the accretion type were raised and fattened under identical conditions with &lt;I&gt;semi ad libitum&lt;/I&gt; feeding of a high energy diet. The animals were used for a digestion trial started at nine months of age and animals were slaughtered at 18 months of age. Body weight (668 vs. 764 kg, &lt;I&gt;P&lt;/I&gt; = 0.011), body weight gain (1 223 vs. 1 385 g/day, &lt;I&gt;P&lt;/I&gt; = 0.043), and body protein gain (93 vs. 128 g/day, &lt;I&gt;P&lt;/I&gt; = 0.001) were lower in H compared to CH bulls. Protein expense per kg protein accretion was higher in H bulls (13.8 vs. 10.2, &lt;I&gt;P&lt;/I&gt; = 0.001). No significant differences were found in concentration and pattern of ruminal short chain fatty acid and in apparent digestibility of organic matter, crude fibre, and N-free extracts. There were no significant differencs in all morphometric traits of rumen mucosa between both cattle breeds. Compared to H, the villi of CH bulls were higher in duodenum (586 vs. 495 &amp;mu;m, &lt;I&gt;P&lt;/I&gt; = 0.001) and proximal jejunum (598 vs. 518&amp;mu;m, &lt;I&gt;P&lt;/I&gt; &lt; 0.001), the crypt were deeper in duodenum (295 vs. 358, &lt;I&gt;P&lt;/I&gt;&lt; 0.001) and proximal jejunum (292 vs. 344 &amp;mu;m, &lt;I&gt;P&lt;/I&gt; = 0.020). In contrast, the villi in ileum were higher in H (522 vs. 471 &amp;mu;m, &lt;I&gt;P&lt;/I&gt; = 0.006). The weight of total small intestine, as percentage of total body weight, was 1.1 in H and 0.8 in CH (&lt;I&gt;P&lt;/I&gt; = 0.002). The utilization of food crude protein was positively related to the duodenal (&lt;I&gt;P&lt;/I&gt; = 0.001) and proximal jejunal villus height (&lt;I&gt;P&lt;/I&gt; = 0.003) and to the duodenal crypt depth (&lt;I&gt;P&lt;/I&gt; &lt; 0.001) and negatively related to weight of small intestine (&lt;I&gt;P&lt;/I&gt; = 0.004). It is concluded, that the higher growth potential and feed efficiency in CH bulls compared to H bulls is not caused by differences in digestion processes, but in size of small intestine, and morphology of small intestinal mucosa. Obviously the duodenum and proximal jejunum of CH bulls adapt to increase the absorptive surface due to the increase in nutrient demand.

Nitrogen in vivo digestibility and in situ degradability data for estimation of lower tract N digestibility with or without correction for microbial contamination

In situ degradability and in vivo (by difference) digestibility trials were conducted to estimate lower tract residual N digestibility (LTRND) of five protein supplements. Efforts were also made to improve the in situ method of measuring protein degradability. For in situ degradability trials, soybean meal (SBM), corn gluten meal (CGM), cotton seed cake (CSC), wheat bran (WB) and corn gluten feed (CGF) were weighed into Dacron bags and incubated in the rumen of three cannulated Chios ewes. SBM, CGF and WB were degraded significantly, while CGM and CSC were least degraded. Microbial contamination (MC) resulted in a 5.3–28.3% artificially decrease in effective ruminal protein degradation of supplements. Total tract digestibility was measured using five rams in an in vivo, by difference, trial using a 5 × 5 Latin-square design. SBM had higher CP digestibility compared to WB, CGF and CSC, and higher N free extract (NFE) digestibility compared to the other feeds. CGM showed higher CP digestibility compared to WB, CGF or CSC, while CGF had higher organic matter (OM) and crude fibre (CF) digestibility compared to WB. CSC was the protein source with the lowest digestibility of OM, CP and NFE in comparison with the other feeds. LTRND was predicted as 0.928, 0.806, 0.227, 0.540, and 0.498 for SBM, CGM, CSC, WB, and CGF, respectively, or 0.931, 0.803, 0.147, 0.364, and 0.316 when the correction for MC was applied. Lower tract N digestibility could be predicted via a combination of in situ degradability and in vivo apparent digestibility data. This approach yields significant data regarding LTRND estimation of protein supplements, while diminishing animal suffering by avoiding small intestinal fistulation.

A note on the effect of triacylglycerols of caprylic and capric fatty acid on performance, mortality, and digestibility of nutrients in young rabbits

Two experiments, an apparent digestibility trial and a feeding experiment, were carried out to evaluate the effect of medium-chain fatty acids (MCFA) supplied as triacylglycerols (TAG) to a diet of growing rabbits. Hyplus rabbits weaned at the age of 35 days were used. In the digestibility trial 20 rabbits were housed individually, in the feeding experiment 216 rabbits were housed four per cage. Rabbits of experimental groups received a diet supplemented with 10 g kg −1 of Akomed R (TAG of caprylic and capric acid). Coefficient of total tract apparent digestibility (CTTAD) of dry matter, N-free extract and ash was higher by 3.4, 3.8 and 9.9%, respectively, in rabbits fed the diet with Akomed R than in control rabbits (P<0.05). Digestibility of other dietary components, the rate of growth, feed intake and carcass yield were not significantly affected. In the feeding experiment, mortality of treated rabbits (15.7%) was significantly lower than that of control rabbits (27.8%; P=0.048). No effect on growth rate and shedding of Eimeria sp. oocysts was observed. It can be concluded that MCFA supplied as TAG of caprylic and capric acid in a commercially available oil significantly decreased high mortality of growing rabbits under practical field conditions, without affecting the rate of growth, feed intake and carcass yield.