The purpose of the present research is to study the effects of different levels of Aloe vera gel on microflora population, humoral and cellular immune response, and relative weight of lymphoid organs compared to the effects brought about by antibiotic. The groups included the control group (basal diet) as well as three groups with different levels of Aloe vera gel (added to basal diet at 1.5%, 2% and 2.5%), and finally a group with basal diet supplemented by 15 ppm virginiamycin antibiotic. Regarding ileum microflora, the increase in Aloe vera gel in the feed resulted in significant reduction in the number of E. coli colonies and significant increase in the number of Lactobacillus colonies compared to the control and antibiotic groups. As far as humoral immunity is concerned, Newcastle disease virus antibody titre on the 24th and 38th day was the highest in 2.5% and 2% Aloe vera gel groups, respectively. In addition, sheep red blood cells antibody titre reached its highest level in the 2.5% Aloe vera gel group on the days 24, 28, 34 and 38. The differences among the groups regarding sheep red blood cells antibody titre were significant on the days 24, 28 and 34, while no significant differences were observed on the 38th day. Regarding the cellular immunity, the highest response was obtained by injecting phytohemagglutinin-P and the highest relative weight of spleen and bursa of Fabricius was found in the 2.5% Aloe vera gel group. The findings of the study suggest reduction in number of E. coli colonies and increase in number of Lactobacillus colonies as a result of increased Aloe vera gel in the feed. Furthermore, the 2.5% Aloe vera gel group resulted in significantly higher levels of humoral and cellular immunity, as well as relatively greater weight of lymphoid organs, which suggests that Aloe vera gel can be a proper replacement for the virginiamycin antibiotic.

Prohibition of application of antibiotic growth promoters in broiler chicken diets has resulted in increased use of herbs as natural additives in broiler feeds over the recent years. researchers particularly look for herbs that can affect such parameters as growth performance, immune response, or treatment of certain diseases. Aloe vera is a well-known herb characterized by properties such as anti-bacterial, anti-viral, anti-fungal, anti-tumor, anti-inflammatory, immunomodulatory, wound-healing, anti-oxidant, and anti-diabetic effects. during the past years, attention has shifted toward Aloe vera as a natural additive to broiler diets, and studies have shown that Aloe vera can improve immune response and growth performance in broilers. in addition, Aloe vera is an excellent alternative for antibiotic growth promoters and anticoccidial drugs. since Aloe vera can be used for broilers in the form of gel, powder, ethanolic extract, aqueous extract, and a polysaccharide contained in Aloe vera gel (i.e. acemannan), more studies are required to determine the best form and to compare Aloe vera with other medicinal herbs. this paper reviews effects of Aloe vera on intestinal microflora, growth performance, immune response, and coccidiosis in broiler chickens.

The present study attempts to analyze the effects of different levels of Aloe vera gel as an alternative to antibiotic, on performance and ileum morphology in broilers. Three hundred one-day old Ross 308 male broilers were used on a completely randomized design in 5 groups with 4 replicates, each consisting of 15 broilers. The groups included the control group (basal diet) and three groups with basal diet mixed with different levels of Aloe vera gel (1.5%, 2% and 2.5%). Finally, there was a group with basal diet plus 15 ppm antibiotic virginiamycin. The results obtained regarding performance of the broilers showed that Aloe vera gel groups brought about higher body weight gain and feed intake compared to the control group; however, no significant difference was observed in feed conversion ratio between the groups treated by Aloe vera gel and the control group (P>0.05). Although the antibiotic group showed better performance and heavier dressing percentage than the Aloe vera gel and the control groups, no significant difference was seen between the group treated by 2% Aloe vera gel and the antibiotic group regarding body weight gain, feed conversion ratio and dressing percentage (P>0.05). Among the Aloe vera gel groups, the 2% Aloe vera gel group had the largest villus height and the greatest villus height to crypt depth ratio compared to the antibiotic group (P<0.05). In general, 2% Aloe vera gel treatment may be recommended to achieve the best performance in broilers as an alternative to antibiotic growth promoter.

The aim of this paper was to investigate the effects of soybean oil, an oilseed rich in the polyunsaturated fatty acid C18:2, on dry matter intake (DMI), milk yield (MY) and milk composition (including fatty acid profile) of dairy cows by using a meta-analysis approach. In the meta-analysis, effect size for all outcomes was reported as standardised means difference with 95% confidence intervals. Q test and I 2 were calculated to detect the heterogeneity, with a metaregression also used to investigate sources of heterogeneity. Results of the meta-analysis indicated that adding soybean oil to the diet of dairy cows decreased DMI, milk fat percentage (MFP), milk fat yield (MFY) and milk protein percentage (MPP), whilst significantly increasing MY. Unsaturated fatty acids C18:2, C18:1 trans-11 and C18:2 cis-9 trans-11 conjugated linoleic acid (CLA) all significantly increased with soybean oil inclusion in the diet, whereas C18:3 was numerically higher but not significantly different. Milk composition, including MFP, MFY, MPP, shortchain and medium-chain fatty acids (C4-C20) and unsaturated fatty acids showed a significant percentage of heterogeneity. Results of the meta-regression indicated that dose of soybean oil, total fatty acids in the diet, and the concentration of C18:2 between groups receiving soybean oil and control are the most important factors affecting this heterogeneity. By performing metaanalysis and meta-regression it can be concluded that dietary supplementation of soybean oil to lactating dairy cows decreased DMI, and increased MY and the amount of unsaturated fatty acids in milk. HIGHLIGHTS Soybean oil dietary supplementation to dairy cows increased milk yield but reduced milk fat content. Milk fat in soybean oil dietary supplemented cows has a lower content of short-chain fatty acids, associated with de novo synthesis. Milk fat in soybean oil dietary supplemented cows has a higher content of C18:1 trans-11, C18:2 and CLA.