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SUMMARYThe effect of feeding two levels of Saccharomyces cerevisiae on the performance of crossbred Friesian calves was investigated. Twenty-four neonatal male Friesian × Baladi calves (35·5 ± 0·25 kg of initial body weight) were randomly assigned in a completely randomized design into three experimental groups for 90 days (eight calves per group). Calves fed their diets without yeast (S. cerevisiae) were considered as Control, while the diets of other calves were supplemented daily either with 2·5 g (YL diet) or with 5 g (YH diet) of yeast per calf. Calves fed the YH diet showed increased feed intake, while dry matter and fibre digestibilities were increased in calves fed YH and YL diets. Calves fed YL and YH diets showed lower ruminal ammonia-N and higher total volatile fatty acids, acetate and propionate concentrations than Control calves. Both YH and YL calves showed increased plasma concentrations of total protein, globulin and glucose and decreased cholesterol and triglycerides concentrations. Calves’ final weight and daily gain were increased with S. cerevisiae yeast supplemented diets. After 42 days of experiment, Clostridium spp., Escherichia coli and Enterobacteria spp. counts were down to undetectable levels in the faeces of calves fed S. cerevisiae additive. It could be concluded that adding S. cerevisiae to milk-fed calves increased feed utilization and improved pre-weaned calf performance and health status, reducing faecal pathogenic bacteria.

Using of natural plants as immunostimulant in fish is more useful than antibacterial drugs that cause adversely side effects for fish, environment and consumers. Therefore, the present study was to investigate the effects of dietary turmeric (Curcuma longa), rosemary (Rosmarinus officinalis) and thyme (Thymus vulgaris) as feed additives on growth performance, proximate composition and some immuno-hematological parameters on Nile tilapia. Four nitrogenous (31.43-31.56 % crude protein) and isocaloric (17.90-18.04 kJ/g) diets were formulated to contain 0% (control), 1% of turmeric, rosemary or thyme, respectively. The results reveled that, supplementation with medicinal herbs significantly increased (P<0.05) weight gain, specific growth rates and protein efficiency ratio (PER) compared to those in the control group. Moreover, the medicinal herb additives had insignificant effect on carcass composition and some biochemical composition. Hematocrit and leukocrit levels in the fish fed with turmeric, rosemary and thyme added diet were found to be significantly (P <0.05) higher than the control group. However, leukocyte level among the experimental groups was not significantly differed (P >0.05). In neutrophils of experimental fish groups, there were higher numbers of NBT (+) cells fixed on lamellas than those of the control group. So, based on the current findings together with the low cost and the immunostimulative effect of turmeric, rosemary and thyme it can be recommended to be used in fish feed to minimize the mortalities caused by some pathogens.

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We investigated the mode of action of 6-(3,4-dichlorophenoxy-3-(ethylthio)-2-pyridincarbonitrile against poliovirus. This agent effectively blocked the synthesis of poliovirus proteins and RNA when it was added at the beginning of infection. Poliovirus attachment and internalization into HeLa cells were not inhibited in the presence of the compound; poliovirus uncoating was the target of its activity. Antiviral agents are of significant interest for at least two main reasons: (i) to provide a remedy for virus-caused diseases and (ii) as tools to get insights into the molecular mechanisms by which animal viruses replicate (3,4,9). A search for new antipicornavirus agents led to the discovery of 2-(3,4-dichlorophenoxy)-5-nitrobenzonitrile as a broadspectrum antiviral agent (17). Initial studies on its mode of action indicated that this compound acted at an early step, after uncoating, that is required for viral RNA synthesis (19). Based on these findings, several phenoxybenzenes and phenoxypyridines were analyzed by Kenny et al. (11). 6-(3,4-Dichlorophenoxy)-3-(ethylthio)-2-pyridincarbonitrile (DEPC) showed the best antipicornavirus activity (11). It was particularly effective against several rhinoviruses, coxsackievirus A21, echovirus 12, and poliovirus 2. Since this compound was inactive against coxsackievirus when added 3 h after infection, it was suggested that DEPC blocked an early step of virus growth. Indeed, the uncoating of photosensitized coxsackievirus A21 was reduced when 2 ,Lg of this compound per ml was present (11). However, this test does not discriminate between the binding of virus particles to cells, its internalization, and viral uncoating. As yet, no studies are available on the potential inhibition of virus attachment by these agents.Poliovirus type 1 (Mahoney strain) was grown in HeLa cells. The procedures for cell culture and the plaque assay for virus titration were as described previously (8). The compound DEPC was kindly given by Merrell-Dow Pharmaceuticals (Indianapolis, Ind.). The full-length poliovirus genome probe was obtained by EcoRI restriction enzyme digestion of the pSVO poliovirus vector. The restriction fragment was recovered from low-melting-point agarose gels by electrophoresis and was labeled with [a-32P]dATP (400 Ci/mmol; The Radiochemical Centre, Amersham, England) by nick translation. HeLa cells were infected with poliovirus at -1 h in Dulbecco modified Eagle medium supplemented with 2% heat-inactivated newborn calf serum. One hour later (0 h), unattached virus was removed, the cell monolayer was washed twice, and fresh medium was added.To assay for protein synthesis cells were incubated in methionine-free medium in the presence of 5 ,uCi of[35S]methionine (1,100 Ci/mmol; The Radiochemical Centre) per ml. One hour later, the medium was removed, and the proteins were collected for electrophoresis in 15% polyacrylamide gels as previously described (1, 5). To obtain specific * Corresponding author. incorporation of [3H]uridine into viral RNA, 5 pug of actinomycin D (Sigma C...