No abstract

A 2 x 2 x 2 factorial arrangement of treatments was conducted to evaluate the effects of two dietary apparent metabolizable energy (AME) levels (2,720 and 2,580 kcal kg-1 diet) and enzyme (0 and 0.3 g kg-1 diet, Grindazym® GP 15,000 with mostly xylanase activity) supplementation on the performance of laying hens fed diets based on two wheat cultivars (Marvdasht and Sardari). Experimental diets were formulated to have a constant energy to protein ratio and were fed to 65-wk-old Lohmann LSL-Lite laying hens for 7 wk. The lower level of AME reduced egg production and egg mass (p<0.05) and increased feed conversion ratio (p<0.05). Enzyme addition increased feed intake of the birds fed a diet with Sardari cultivar (p<0.05) but had no effect on feed intake of the birds fed a diet with Marvdasht cultivar (p>0.05). Nevertheless, birds receiving diets based on Marvdasht cultivar had higher feed intake and egg mass than that of those receiving diets based on Sardari cultivar (p<0.05). The birds fed diets based on Marvdasht cultivar produced less undesired eggs and had better yolk color as compared with the birds fed diets based on Sardari cultivar (p<0.05). The serum concentration of glucose increased by enzyme supplementation when birds receiving lower AME level (p<0.05). These results indicate that enzyme supplementation may have a positive effect on the feed intake of laying hens when fed on wheat-based diets; however, this effect is cultivar dependent and does not necessarily mean that enzyme supplementation always benefit production.

This study was conducted to evaluate the effects of the particle size (PS) of alfalfa hay (AH) and soybean hull (SH) on milk production of dairy cows and the population of major cellulolytic bacteria in the rumen. Eight lactating Holstein cows, averaging 590±33 kg BW and 47±13 days in milk (DIM ), were assigned in a 4×4 Latin square design to a 2×2 factorial arrangement of treatments: alfalfa hay particle size (fine vs. coarse) combined with soy hull (zero or substituted as 50% of AH). The cows were fed diets formulated according to NRC (2001). Physically effective factor (pef) and physically effective fiber (peNDF) contents of diets increased by increasing AH particle size and inclusion of SH in the diets (p<0.01). Dry matter intake was not significantly affected by treatments but intake of peNDF was increased marginally by increasing the PS of AH (p = 0.08) and by SH inclusion (p<0.01) in the diets. Milk production was increased by feeding diets containing SH (p = 0.04), but it was not affected by the dietary PS. Milk fat content was increased by increasing AH particle size (p = 0.03) and decreased by SH substitution for a portion of AH (p<0.01). The numbers of total bacteria and cellulolytic species were not affected by PS of AH or by SH. F. succinogenes was the most abundant species in the rumen followed by R. albus and R. flavefaciens (p<0.01). This study showed that SH cannot replace the physically effective fiber in AH having either coarse or fine particle size. In diets containing SH, increasing of diet PS using coarse AH can maintain milk fat content similar to diets without SH. Particle size and peNDF content of diets did not affect the number of total or fibrolytic bacteria in the rumen.

______________________________________ __________________________________________ tcartsbAThe present study was conducted to determine the effect of including different levels of whole cottonseed (WCS) in the finishing diet of lambs on their dry matter intake (DMI), live weight gain, feed conversion ratio (FCR, kg feed/kg gain), carcass characteristics and small intestinal morphology. Twenty Zandi male lambs (29.8 ± 1.6 kg body weight) were assigned to one of four diets in a completely randomized experimental design. The experimental diets contained 0%, 4%, 8% and 16% WCS on a dry matter (DM) basis. The diets were prepared as total mixed rations and fed to the lambs ad libitum. The lambs were slaughtered on day 90 and carcass data was collected. The DMI and average daily gain (ADG) were significantly greater for lambs fed the 8% WCS diet compared with the other treatments. The FCR was significantly lower in the diets containing WCS compared to the control, viz. 6.11, 5.6, 5.46 and 5.68, for treatments 0, 4, 8 and 16% of WCS, respectively. However, the positive effects of including 8% cottonseed in the diet were significant in hot carcass weight, dressing percentage, liver, fat tail, intestinal fat and spleen compared with the control group. Furthermore, villous morphology and depth of crypt gland were affected by both diet and sampling site. No negative effects were observed in the organs and carcasses of the lambs that received different diets. The results indicate that the inclusion of 8% WCS in lamb diets could have a positive effect on most of the traits, but increasing the WCS inclusion up to 16% in the diet may have negative effects on lamb performance.

An experiment was conducted to study the effects of extruded cotton seed (ECOS) and canola seed (ECAS) in the diet of male Mehraban lambs on the concentration of unsaturated fatty acids in their plasma, erythrocytes and livers. The treatments were: (1) control (C); (2) diet C+6% ECAS, (3) diet C+6% ECOS, (4) diet C+12% ECAS, (5) diet C+12% ECOS, (6) diet C+6% ECAS+6% ECOS, (7) diet C+12% ECAS +6% ECOS, (8) diet C+6% ECAS +12% ECOS, (9) diet C+12% ECAS+12% ECOS, (10) diet C+18% ECAS+18% ECOS. A complete randomized experimental design was applied. Sixty lambs (5 -6 months of age) were randomly allocated to the 10 dietary treatments in order to have six lambs (replicates) per diet. The lambs were housed in individual pens. The average weight of lambs at the onset of the study was 34.3 ± 2.12 kg. The experiment lasted for 90 days. Results indicated that the concentration of oleic acid (C18:1), linoleic acid (C18:2 n-6) and linolenic acid (C18:3 n-3) in the plasma and oleic acid and linolenic acid in erythrocyte lipids were higher in lambs fed diets containing oil seeds or a combination of the oil seeds compared to those receiving the control diet. The supplementation of 6% and 12% ECAS increased the linoleic acid concentration in the liver lipids significantly compared to those fed the diets containing ECOS. There was a linear correlation between linoleic acid content of the liver and levels of dietary ECAS and ECOS. This study provides evidence that dietary oleic acid, linoleic acid and linolenic acid might escape biohydrogenation in the rumen and showed that the type of dietary fat has a marked impact on lipid metabolism in the liver. ________________________________________________________________________________