This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authorsare permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t Summary:The aim of the study was to determine the influence of increasing levels of urea (i.e., 0 (U0); 10 (U10); and 15 (U15) g kg -1 of concentrate) in sheep fed diets containing dates (local name: Azzawi), on nutrient intake and digestibility, N utilisation and ruminal fermentation. To maintain iso-nitrogenous and iso-metabolisable energy diets, the dates were added with increasing levels of urea. Sheep were fed a 400:600 (dry matter (DM) basis) concentrate:berseem hay (Trifolium alexandrinum) diet. Twelve Barki sheep (53.8 7 1.95 kg body weight) with three/diet were used in a randomised block design to determine digestibility and N balance, while four ruminally cannulated Barki sheep (56.6 7 2.15 kg body weight) were used in a 3 Â 3 Latin square design to determine rumen function. Experimental periods were 22 days with the first 15 days for adaptation. The calculated metabolisable energy (MJ kg -1 DM) and actual crude protein (CP; g kg -1 DM) contents were 12.17 and 156.1, 12.69 and 158.2 and 12.60 and 154.8, for the U0, U10 and U15 diets, respectively. Increased urea feeding increased (P o 0.05) digestibility of DM, organic matter (OM) and CP. Rumen ammonia N concentrations, allantoin in urine and the resultant microbial N supply increased linearly (P o 0.05), as did the total ruminal volatile fatty acid concentrations. Results suggest that urea supplementation to sheep diets containing dates improved DM, OM and CP digestibility and substantially increased rumen microbial growth as well as ruminal fermentation function. Crown

our groups of male lambs (seven animals/ group) were used to study the effect of natural (garlic powder; Allium sativum) and biological (dry yeast; Saccharomyces cerevisiae) additives and their combination in finishing diets as compared to control diet on feed utilization and animal performance. Animals were 8 months of age and 35.8kg ± 0. 41 as average body weight. Animals were fed a basal diet including concentrate feed mixture (CFM) at level of 70% of total requirement and berseem hay (BH) was offered ad lib. The experimental diets were: 1) a basal diet without additive (control), (C); 2) a basal diet supplemented with 6g dry yeast (2.44x10 11 cfu/g)/head/day, (Y); 3) a basal diet supplemented with 40g garlic powder/head/day, (G), and 4) a basal diet supplemented with 3g dry yeast plus 20g garlic powder/head/day, (YG). The results revealed that all feed additive treatments showed higher (P<0.05) digestibility values of DM, OM, CP, CF and NFE, than non-additive diet (C). The highest (P<0.05) values were observed for animals fed G diet; however, C group showed the lowest (P<0.05) digestibility values. The G diet showed the highest (P<0.05) value of TDN% (73.56%) and C showed the lowest one (69.20%). However, the DCP% was not affected (P<0.05) by additives and its values ranged between 11.81 and 12.27%. Animals fed enriched diets (Y, G and YG) showed higher ADG (180, 184 and 186 g/d, respectively) compared to control group (160g/d). Additives have no significant effect on feed intake either in the form of CFM or the roughage and consequently the total feed intake. All feed additives and their combination significantly (P<0.05) enhanced, with the same extent, the feed efficiency indicators of the enriched diets compared with control one. Yeast/garlic combined addition revealed the highest daily profit percentage relative to control (42%) followed by garlic (34.0%) and then yeast alone (31%) treatments. Energy utilization was significantly different (P<0.05) between the test groups where, the G group showed the highest values, but C group was the lowest values. When the combined additive (YG) was supplemented, N balance exhibited 15.2% increase above the control group. The concentration of blood immunoglobulins (IgA) and IgG differed (P <0.05) among groups being their concentration were enhanced by the respective additives. It could be concluded that using feed additive such as dry yeast (6 gm/h/d) or garlic powder (40 gm/h/d) or their combination (3gm plus 20 gm, respectively) in finishing diets of lamb tended to increase digestibility coefficients for most of nutrients, increasing nutritive value as TDN and appeared to increase the daily gain as well as enhanced the immune status of animals.

Rumen bacteria make the greatest contribution to rumen fermentation that enables the host animal to utilize the ingested feeds. Agro-industrial byproducts (AIP) such as olive cake (OC) and date palm byproducts (discarded dates (DD), and date palm fronds (DPF)) represent a practical solution to the deficiency in common feed resources. In this study, thirty-six growing Barki lambs were divided into three groups to evaluate the effect of untraditional diets including the AIP on the growth performance. Subsequently, nine adult Barki rams were used to evaluate the effect of experimental diets on rumen fermentation and rumen bacteria. Three rations were used: common concentrate mixture (S1), common untraditional concentrate mixture including OC and DD (S2), and the same concentrate mixture in S2 supplemented with roughage as DPF enriched with 15% molasses (S3). The animals in S2 group showed higher dry matter intake (DMI) and lower relative growth rate (RGR) as compared to the animals in S1 group. However, the animals in S3 group were the lowest in DMI but achieved RGR by about 87.6% of that in the S1 group. Rumen pH, acetic and butyric acids were more prevalent in animals of S3 group and rumen ammonia (NH3-N), total volatile fatty acids (TVFA), propionic acid were higher in S1. Rumen enzymes activities were higher in S1 group followed by S3 and S2. The bacterial population was more prevalent in S1 and microbial diversity was higher in the S3 group. Principal coordinate analysis revealed clusters associated with diet type and the relative abundance of bacteria varied between sheep groups. The bacterial community was dominated by phylum Bacteroidetes and Firmicutes; whereas, Prevotella, Ruminococcus, and Butyrivibrio were the dominant genera. Results indicate that diet S3 supplemented by OC, DD, and DPF could replace the conventional feed mixture.

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<abstract> <p>Rumen methanogens prevent the accumulation of fermentation gases in the rumen and generate methane that increases global warming and represents a loss in animals' gross energy. Non-traditional feed resources such as the by-products of date palm (<italic>Phoenix dactylifera</italic>) and olive (<italic>Olea europaea</italic>) trees have received attention to be used in animal feeding. This study evaluated the impact of non-traditional feed resources including olive cake (OC), discarded dates (DD), and date palm frond (DPF) in sheep diet on rumen fermentation, diversity and relative abundance of rumen methanogens. Nine adult rams were assigned to three equal groups and fed three diets: traditional concentrates mixture (S1); non-traditional concentrate mixture (S2) based on DD and OC; and (S3) composed of the same S2 concentrate supplemented with DPF as a roughage part. The results showed that rumen pH was higher with S3 diet than the other two diets. However, the S1 diet showed the highest values of total volatile fatty acids (TVFA) and rumen ammonia. In addition, the proportions of acetic and butyric acids were increased, whereas propionic acid declined in S2 and S3 compared to the S1 diet. Rumen methanogens were dominated by <italic>Methanobrevibacter</italic> that showed a numeric decline by including DD, OC, and DPF in the animal diets. Principal component analysis (PCA) based on rumen fermentation parameters and relative abundances of methanogens genera showed three distinct clusters. Also, positive and negative correlations were revealed between methanogens genera and rumen metabolites. This study expands the knowledge regarding the effect of agricultural byproducts on rumen fermentation and the methanogenic community.</p> </abstract>