The use of vitamin K deficient diets in the screening and evaluation of anticoccidial drugs

Administration of Ethanolic Extract of Spinacia oleracea Rich in Omega-3 Improves Oxidative Stress and Goblet Cells in Broiler Chickens Infected with Eimeria tenella

This study investigated the anticoccidial activity of spinach (Spinacia oleracea) whole-plant extract against Eimeria tenella, both in vitro and in vivo. For this purpose, one hundred 8-day-old broiler chicks of both sexes were divided into four groups (n = 25 in each group). Chicks in the first group served as the negative control (non-treated-non-infected). Chicks in the second group were challenged at 18 days old with 5 × 104E. tenella sporulated oocysts. The third group was challenged with 5 × 104 sporulated E. tenella oocysts at 18 days old after receiving spinach extract at a dose of 50 mg/kg at 8 days old. The fourth group received 0.2 mg/kg diclazuril (Coxiril® 0.2%) in their diet two days before being orally infected with 5 × 104 sporulated E. tenella oocysts and this continued till day 10 post-infection (PI). The growth performance, clinical symptoms, oocyst shedding, histological findings, and biochemical parameters were used to evaluate the efficacy on day 8 PI when the infection was at its peak. A gas chromatography examination revealed that omega-3 fatty acids were the main constituents of the spinach extract, followed by oleic acid, palmitic acid, and phytol, with amounts of 23.37%, 17.53%, 11.26%, and 7.97%, respectively. The in vitro investigation revealed that the spinach extract at concentrations of 10% and 5% inhibited the oocyst sporulation by 52.1% and 45.1%, respectively. The 5% concentration was selected for the in vivo trial based on the results of the in vitro study. The infected-untreated group showed high levels of OPG; lower body weight; a greater number of parasite stages; few goblet cells; decreased SOD, CAT, and GPX levels; and increased MDA and NO levels. The spinach-treated group, on the other hand, showed a significant decrease in oocyst output per gram of feces (OPG), increased body weight, decreased parasitic stages, and a nearly normal number of goblet cells. Additionally, it reduced malondialdehyde (MDA) and nitric oxide (NO), while increasing superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). In conclusion, spinach produced significant antioxidant effects, increased body weight, reduced the number of oocysts and parasite stages in the caecum, and restored the number of goblet cells relative to those of an uninfected control. Furthermore, spinach extract inhibits the sporulation percentage of E. tenella oocysts. The ethanolic extract of S. oleracea (whole plant) contained high concentrations of fatty acids, palmitic acid, Phytol, betulin, and ursolic aldehyde, all of which are known to regulate the antioxidant pathway and modulate inflammatory processes and may be the main reason for its anticoccidial activity.

Effects of whole wheat feeding on the development of coccidial infection in broiler chickens

A complete ground and pelleted feed was compared to free choice feeding of whole wheat and a pelleted protein concentrate during three experimental infections with coccidia in broiler chickens. At 22 d of age birds were inoculated with different doses of sporulated oocysts of a cecal species (Eimeria tenella) in experiment 1 or intestinal species E. maxima or E. acervulina in experiments 2 and 3, respectively. The effects of diets were assessed on weight gain, hematocrit (during cecal coccidiosis), serum coloration (during intestinal coccidiosis), oocyst excretion, and lesion score until 7 d post-inoculation. In experiment 1 before inoculation, the birds fed whole grain had more beneficial microflora with lower counts of coliform bacteria. As shown by oocyst output and lesion score, whole wheat feeding increased parasite development during infection with the cecal parasite E. tenella. This led to significantly lower weight gain with whole wheat than with ground wheat from 5 to 6 d post-inoculation and to lower hematocrit at the highest infective dose. Parasite development in experiments 2 and 3 was similar among diets, during intestinal infection with E. maxima and E. acervulina, respectively, with no significant differences in lesion score. During the acute phase (4 to 7 and 3 to 5 d post-inoculation), when a difference appeared between diets, whole wheat fed-birds were always more affected than ground diet-fed birds in terms of serum coloration and weight gain. These results might be explained by modifications of digestive physiology and intestinal microflora by whole wheat.

Differences between the anticoccidial potencies of monensin in maize-based or wheat-based chicken diets

Experiments were carried out to investigate why the anticoccidial ionophore monensin is more potent against the coccidium Eimeria tenella in chickens fed on a maize-based diet (as in the USA) than in chickens fed on a wheat-based diet (as in the UK). The explanation seems to be that the pathogenicity of E. tenella is lower in maize-fed chickens than in wheat-fed chickens, whether monensin is present in the diet or not. Possible reasons for this are suggested. The better survival of maize-fed birds may be partly due to protective effects of the higher concentrations of vitamins A and E derived from their diet. Furthermore, the higher concentrations of niacin and riboflavin in wheat than in maize may enhance coccidial pathogenicity. These opposing factors might combine to cause equivalent infection levels to produce more severe coccidiosis in chickens fed on a wheat-based diet than on a maize-based diet.

Eimeria tenella, E. necatrix, E. acervulina, E. maxima, and E. brunetti: potent anticoccidial activity of an uridine analog, 1-(beta-D-ribofuranosyl)-2(1H)-pyrazinone 4-oxide

The anticoccidial activity of an uridine analog, 1-(beta-D-ribofuranosyl)-2(1H)-pyrazinone 4-oxide (emimycin riboside), against five species of chicken Eimeria was tested individually in battery experiments. With 16 ppm of the compound in feed, marked anticoccidial activity was obtained against Eimeria tenella, E. necatrix, E. acervulina, E. maxima, and E. brunetti. The last named species was more drug-sensitive than the others--dietary levels of at least 8 ppm of the drug exhibited good protection and eliminated practically all clinical signs. The battery tests with delayed and restricted medications showed that emimycin riboside affected the development of parasites in first and second generation schizogony of the life cycle of E. tenella.

Eimeria tenella, E. necatrix, E. acervulina, and E. maxima: anticoccidial activity of 1,6-dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide

The anticoccidial activity of an orotic acid analog, 1,6-dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide (carboxyemimycin), was tested in battery experiments, utilizing 9-day-old Single-Comb White Leghorn cockerels. Carboxyemimycin, at 125 ppm and more in feed, exhibited marked anticoccidial activities against Eimeria tenella, E. necatrix, E. acervulina, and E. maxima. High doses of carboxyemimycin--up to 1000 ppm--did not cause any reduction in weight gains. The battery and in vitro studies with delayed and restricted medications revealed that carboxyemimycin affected the development of E. tenella in first and second generation schizogony and in gametogony.

Coccidial infection with Eimeria tenella and caecal defaecation in chicks

1. The periodicity of caecal defaecation was investigated in chicks infected with Eimeria tenella. The birds were illuminated for 12 h/d (07.00-19.00) and faeces were collected at 3-h intervals for up to 21 d. 2. In uninfected birds caecal faeces were never collected during the dark period. During the periods 07.00-10.00 h, 10.00-13.00 h, 13.00-16.00 h and 16.00-19.00 h, caecal defaecation occurred on approximately 44, 19, 55 and 91% of the total number of days respectively. 3. In infected birds production of haemorrhagic caecal faeces began from between 90 and 156 h after infection and continued during both light and dark periods for between 12 and 48 h. After this period, no caecal faeces were observed for between 39 and 120 h. Normal caecal defaecation resumed from between 198 and 264 h.

The effect of vitamins A, E and K on experimentally induced histomoniasis in turkeys

Vitamins A, E and K were incorporated into turkey starter rations at normal (1 x ), 5 x and 50 x the National Research Council recommended vitamin levels and evaluated for their effect on histomoniasis in turkeys. Infected as well as comparable unifected poults were included in all trials. Each vitamin was also evaluated at normal and 50 x the NRC level in combination with ipronidazole, a low-level antihistomonal agent. In addition to performance parameters, glutamate oxaloacetate transaminase (GOT) and lactate dehydrogenase (LDH) plasma enzyme levels were used to evaluate the vitamin effect. None of the vitamins tested alone were found to be effective in terms of reducing mortality and morbidity following a severe Histomonas meleagridis challenge, regardless of the vitamin dose. A significant improvement in performance was demonstrated with the vitamin E (50 X)--ipronidazole combination and a numerical improvement with the vitamin A (50 X)--ipronidazole combination over ipronidazole alone or the poults fed NRC recommended vitamin levels. The GOT and LDH plasma enzyme levels correlated well with the progressive pathological changes associated with the disease. At 11 days post-infection both enzymes were consistently and significantly elevated above those of the uninfected controls, irrespective of the vitamin levels provided. The presence of low ipronidazole in most instances delayed the onset of clinical symptoms and was associated with a delay in enzyme elevation, indicating the excellent correlation and sensitivity of the enzyme method in assessing liver damage.