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The effect of chemical composition of sunflower seed meal (SFSM) on TMEn and true amino acid digestibility (TAAD) was studied. In Experiment 1, the excretion pattern of three SFSM samples force-fed (30 g) to 10 adult cockerels (Hy-Line) each was followed for 84 h to determine the time interval for complete excretion of SFSM. Type of SFSM did not affect the excretion pattern of DM and energy (P=0.438, and P=0.189, respectively). Dry matter and energy excreted every 12 h decreased linear and quadratically (P < 0.001) with collection time. No differences were found from 48 h collection time on. So, an excreta collection period of 48 h was considered adequate for determining the TMEn of SFSM. In Experiment 2, 135 adult cockerels were force-fed to determine the TMEn of 11 samples of SFSM. Type of SFSM affected TMEn (P < 0.001), which ranged from 1,558 to 2,023 kcal/kg DM for SFSM of 31 to 42% CP, respectively. The TMEn was highly correlated (P < 0.001) to hemicellulose (r=-0.90), acid detergent lignin (r=-0.84), neutral detergent fiber (r=-0.82), and CP (r=0.77). Four prediction equations are proposed, the most practical being: TMEn (kcal/kg DM)=2,816.8 - 109.5 hemicellulose (%DM), RSD=70.2. Three out of the 11 samples of SFSM were selected for determining TAAD and the effect of endogenous amino acid correction. The methodology used was that of the TMEn assay, but one more estimation of amino acid endogenous excretion was made using a N-free diet with 85% cornstarch and 15% cellulose. Endogenous amino acid excretion was greater for roosters fed the N-free diet than those deprived of feed, resulting in a higher digestibility (from 0.7 to 2.7%, P < 0.05) only for six amino acids: threonine, valine, alanine, proline, and aspartic and glutamic acids. No interaction was detected (P=0.94) between type of SFSM and method of estimation of endogenous amino acid excretion. The TAAD of SFSM increased significantly (P < 0.001) with the CP content, total TAAD being 86, 88, and 89% for SFSM of 32, 35, and 37% CP, respectively. Attention should be paid when including high fiber-low protein SFSM in poultry diets to balance its lesser digestible amino acids contribution, mainly in lysine (from 0.77 to 1.06% for SFSM of 32 and 37% CP, respectively).

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The effect of barley storage time and dietary enzyme addition on the energy value of barley-based broiler diets was studied in two experiments. A two-rowed winter barley (Beka cultivar) was stored at room temperature for 0, 3, 6, 16, and 32 wk after harvesting. At these dates, diets were formulated using 50% barley with and without the addition of a commercial beta-glucanase-based enzyme product. In Experiment 1, 320 Arbor Acres chickens (eight replicates of three 10-d-old birds and eight replicates of one 30-d-old bird, per treatment) were fed the experimental diets to determine the AMEn following a 2 x 2 x 5 (age by enzyme by barley storage time) factorial design. At the end of the metabolism trial, viscosity of the intestinal contents was determined in 30-d-old broilers. Total beta-glucan, nonstarch polysaccharides (NSP), in vitro viscosity, and endogenous enzyme activity of barley grain decreased with increasing storage time. Dietary AMEn increased with barley storage time (from 2,755 to 2,939 kcal/kg DM, P < 0.001, for 0 and 32 wk of storage, respectively), with enzyme addition (2,861 vs 2,919 kcal/kg DM, P < 0.003), and with the age of animals (2,826 and 2,958 kcal/kg DM for 10- and 30-d-old chickens, respectively, P < 0.001). Interactions of enzyme and age by barley storage time (P < 0.02 and P < 0.001, respectively) were also detected. These data indicate that the minimum time of barley storage before its inclusion in broiler feed depends on the animals' age (more than 6 wk for 10-d-old chickens and 3 wk for 30-d-old chickens), and that the use of enzymes allowed a reduction in the time of barley storage. Digesta viscosity decreased with barley storage time (P < 0.001), and with enzyme addition (P < 0.001), an interaction of storage time by enzyme addition was shown (P < 0.007). Digesta viscosity was also negatively related to the dietary AMEn content (r = -0.68, P < 0.01). In vitro barley viscosity explained 53 and 90% of the variation in gut viscosity produced by unsupplemented and enzyme supplemented diets, respectively. In Experiment 2, the same diets as Experiment 1 and the barley grain were intubated into 120 adult roosters (Hy-Line) to determine TMEn. Dietary and barley TMEn values were not affected by barley storage time or enzyme addition (3,237 and 3,037 kcal TMEn/kg DM for diets and barley, respectively).

The role of gut barrier against pathogens and its interaction with dietary factors in weaned rabbits affected with digestive disorders, especially epizootic rabbit enteropathy is reviewed. This interaction was studied identifying nutritive factors that influence gut barrier function of mucosa. It was examined the morphology, and enzyme activity of mucosa and the gut associated immune system. Besides, it was characterized the substrate that reaches the caecum and its capacity to favour pathogen bacteria growth, by reviewing the effect of diet on ileal digestibility of nutrients, transit time and microbiota population. The nutritional factors which affect health of early weaned rabbits are level and type of both fibre and protein. The optimal dietary level of insoluble fibre to minimise mortality is 30-32%. Furthermore, a moderate inclusion of soluble fibre (12%) improves mucosa integrity and decreases mortality and the frequency of detection of Clostridium perfringens and Campylobacter spp in the caecum. The reduction of ileal nitrogen flow had a positive effect on pups viability and frequency of detection of C. perfringens. Furthermore, dietary supplementation with 1% of glutamine reduced fattening mortality, the frequency of detection of C. perfringens, and Helicobacter spp, and diminished the counts of Eimeria spp at the jejunum. In conclusion, a correct diet formulation may help to limit the epizootic rabbit enteropathy incidence in weaned rabbits.Additional key words: fibre, gut barrier function, protein, weaning, young rabbits. ResumenRevisión. Nuevas tendencias en alimentación de conejos. Efecto de la nutrición sobre la salud intestinal En este trabajo se revisa el papel de la barrera intestinal frente a patógenos y su interacción con factores de la dieta en gazapos destetados afectados por enteropatía epizoótica. Para ello, se identificaron los factores nutritivos que influyen en la funcionalidad de la barrera intestinal de la mucosa digestiva (morfología, actividad enzimática y actividad del sistema inmune asociado a la mucosa). Además, se ha caracterizado el sustrato alimenticio que alcanza el ciego y su capacidad para favorecer el crecimiento de bacterias patógenas, revisando el efecto de la dieta sobre la digestibilidad ileal de nutrientes, el tránsito digestivo y el tipo de flora intestinal. Los factores nutricionales involucrados incluyen nivel y tipo de fibra y proteína. El contenido óptimo de fibra insoluble en el pienso para minimizar la mortalidad es un 30-32%. Además, una inclusión moderada de fibra soluble (12%) mejoró la integridad de la mucosa y redujo la mortalidad y la frecuencia de detección de Clostridium perfringens y de Campylobacter spp en el ciego. Un descenso del flujo ileal de nitrógeno tuvo también un efecto positivo sobre la viabilidad de los gazapos y la frecuencia de detección de C. perfringens. La suplementación del pienso con un 1% de glutamina redujo la mortalidad en cebo y la frecuencia de detección de C. perfringens y Helicobacter spp, y disminuyó los conteos de Ei...