K. Ghareeb

Effects of dietary inclusion of probiotic and synbiotic on growth performance, organ weights, and intestinal histomorphology of broiler chickens

A feeding trial was conducted to investigate the effects of dietary supplementations of synbiotic and probiotic on broiler performance, carcass yield, organs weights, and histomorphological measurements of small intestine. Six hundred 1-d-old broiler chicks were randomly assigned to 1 of 3 dietary treatments for 5 wk. The dietary treatments were 1) control, 2) basal diets supplemented with synbiotic (1 kg of Biomin IMBO/ ton of the starter diets and 0.5 kg/ton of the grower diets), 3) basal diets supplemented with probiotic (1 kg of a homofermentative and a heterofermentative Lacto-bacillus sp./ton of feed). The BW, average daily weight gain, carcass yield percentage, and feed conversion rate were significantly (P < 0.05) increased by the dietary inclusion of the synbiotic compared with the control and probiotic-fed broilers. Moreover, a slight improvement in performance traits was observed in broilers fed the probiotic compared with control birds. The absolute and relative weight of spleen and thymus tended to be greater (P < 0.1) for the probiotic-supplemented group compared with the synbiotic-supplemented group. The relative liver weight was greater (P < 0.05) for probiotic-fed birds compared with synbiotic-fed birds. Additionally, the weight of small intestine was greater for either probiotic- (3.17) or synbiotic-fed birds (3.11) than the controls (2.89). Furthermore, dietary treatments influenced the histomorphological measurements of small intestinal villi. The addition of either probiotic or synbiotic increased (P < 0.05) the villus height:crypt depth ratio and villus height in both duodenum and ileum. The duodenal crypt depth remained unaffected (P > 0.05). However, the ileal crypt depth was decreased by dietary supplementations compared with control. In conclusion, synbiotic or probiotic displayed a greater efficacy as growth promoters for broilers. Furthermore, the dietary supplementations resulted in an increase in the villus height and crypt depth of intestinal mucosa of broilers. The increase in the villus height and villus height:crypt depth ratio was associated with improvement of growth performance for both synbiotic and probiotic. This indicates that the synbiotic and probiotic can be used as a growth promoter in broiler diets and can improve the gut health. These products show promising effects as alternatives for antibiotics as pressure to eliminate growth-promotant antibiotic use increases.

Measurement of corticosterone metabolites in chicken droppings

1. A non-invasive technique for stress assessment is needed. Therefore, an enzyme immunoassay (EIA) for measurement of glucocorticoid metabolites in chicken droppings was established and validated. 2. Radiolabelled corticosterone was administered intravenously to detect the time course of excreted metabolites. The metabolites were then characterised by chemical and immunological methods to find a suitable antibody. 3. Reversed-phase high-performance liquid chromatography (RP-HPLC) separations of the peak concentration samples revealed that corticosterone was extensively metabolised, mainly to more polar substances. 4. HPLC fractions were tested in several EIAs for glucocorticoid metabolites, where the highest quantities were detected by a newly established cortisone assay, measuring metabolites with a 3,11-dione structure. 5. The biological relevance of this cortisone EIA was confirmed by stimulation of adrenocortical activity by adrenocorticotropic hormone (ACTH). 6. With this newly developed EIA it should be possible to measure adrenocortical activity non-invasively in chickens and other galliformes, thus providing a tool for a variety of research fields, such as poultry production, ethology and behavioural ecology.

Intestinal Structure and Function of Broiler Chickens on Diets Supplemented with a Synbiotic Containing Enterococcus faecium and Oligosaccharides

A feeding trial was conducted on broiler chickens to study the effects of the synbiotic BIOMIN IMBO [a combination of Enterococcus faecium, a prebiotic (derived from chicory) and immune modulating substances (derived from sea algae)], with a dose of 1 kg/ton of the starter diets and 0.5 kg/ton of the grower diets on the intestinal morphometry and nutrient absorption. The general performance was improved (P < 0.05) by the dietary inclusion of synbiotic compared with the controls. Furthermore, the addition of synbiotic increased (P < 0.001) the villus height/crypt depth ratio and villus height in ileum. However, the ileal crypt depth was decreased by dietary supplementation of synbiotic compared with control. The addition of glucose in Ussing chamber produced a significant increase (P ≤ 0.001) in short-circuit current (Isc) in jejunum and colon relative to the basal values in both synbiotic and control groups. However, in jejunum the percentage of Isc increase after glucose addition was higher for synbiotic group (333 %) than control group (45 %). In conclusion, dietary inclusion of synbiotic BIOMIN IMBO increased the growth performance and improved intestinal morphology and nutrient absorption.

Decontamination and detoxification strategies for the Fusarium mycotoxin deoxynivalenol in animal feed and the effectiveness of microbial biodegradation

Trichothecenes are a group of mycotoxins mainly produced by fungi of the Fusarium genus. Deoxynivalenol (DON) is one of the most abundant and important trichothecenes in food and feed, and is a significant contaminants due to its frequent occurrence in toxicologically relevant concentrations worldwide. Since toxin production depends strongly on environmental conditions, such as temperature and humidity, Fusarium toxin contamination can not be avoided completely. Therefore, exposure to this toxin is a permanent health risk for both humans and farm animals. As cereal crops are commonly contaminated with DON and animal diets consist mainly of cereals, it can be assumed that animals are frequently exposed to DON-contaminated feeds. Many strategies can be undertaken to reduce the toxic effect of DON. In addition to the general necessity for minimizing all risk factors that might influence the contamination of cereals with DON, such as the so-called field toxins before harvest, several post-harvest strategies can be applied to counteract possible deleterious effects of this mycotoxin in farm animals. Another approach for decontamination in feedstuffs is the use of adsorbent materials. Adsorbent materials may bind mycotoxins in the gastrointestinal tract and reduce absorption and systemic toxicity. It has been shown that some adsorbents are suitable to alleviate the toxic effects of specific mycotoxins, but its efficacy against trichothecenes is practically zero. Therefore, alternative strategies to reduce animal and human health risk are needed. The use of microbial additives is a method which uses microorganisms having the capability to detoxify mycotoxins by metabolism or degradation prior to their resorption in the gastrointestinal tract. DON has been reported to be completely transformed to de-epoxy-DON by ruminal and intestinal microflora. Eubacterium BBSH 797 was capable of DON degradation and counteracted the toxic effects of DON in animals. This review focuses on the efficacy of microbial feed additives in ameliorating the toxic effects of DON. According to the results of experiments to date, it appears that microorganisms are the main living organisms suitable for this mycotoxin biodegradation. However, the use of this approach depends on its effectiveness from both a practical and economic perspective.

Evaluating the efficacy of an avian-specific probiotic to reduce the colonization of Campylobacter jejuni in broiler chickens

Campylobacteriosis is the most frequent zoonotic disease in humans worldwide, and the contaminated poultry meat by Campylobacter jejuni can be considered one of the important sources of enteric infections in humans. The use of probiotics, which can help to improve the natural defense of animals against pathogenic bacteria, is an alternative and effective approach to antibiotic administration for livestock to reduce bacterial contamination. In vitro experiments showed that Enterococcus faecium, Pediococcus acidilactici, Lactobacillus salivarius, and Lactobacillus reuteri isolated from healthy chicken gut inhibited the growth of C. jejuni. To demonstrate this effect in vivo, 1-d-old broiler chicks received 2 mg/bird per day of a multispecies probiotic product via the drinking water. Controls received no probiotic treatment, and all chicks were infected with C. jejuni orally. Results showed that the cecal colonization by C. jejuni was significantly reduced by probiotic treatment at both 8 and 15 d postchallenge. To confirm this effect, in a second in vivo experiment, 1-d-old broiler chicks received the same dose of the same probiotic via the drinking water and controls received no probiotic, and all chicks were infected with C. jejuni orally. Similarly, probiotic treatment reduced (P=0.001) cecal colonization by C. jejuni at both 8 and 15 d postchallenge. The results of our in vivo experiments conclude that probiotic administration reduced the colonization of C. jejuni in broiler chickens.

Effect of addition of a probiotic micro-organism to broiler diet on intestinal mucosal architecture and electrophysiological parameters.

Probiotics might be one of the solutions to reduce the effects of the recent ban on antimicrobial growth promoters in feed. However, the mode of action of probiotics still not fully understood. Therefore, evaluating probiotics (microbial feed additives) is essential. Thus the objective of this work was to investigate the efficacy of a new microbial feed additive (Lactobacillus salivarius and Lactobacillus reuteri) in broiler nutrition. The body weight (BW), average daily weight gain was relatively increased by the dietary inclusion of Lactobacillus sp. in broiler diets. Furthermore, the Lactobacillus feed additive influenced the histomorphological measurements of small intestinal villi. The addition of Lactobacillus sp. increased (p < 0.05) the villus height (VH)/crypt depth ratio and the VH was numerically increased in duodenum. The duodenal crypt depth remained unaffected (p > 0.05), while the ileal crypt depth was decreased by dietary supplementation of Lactobacillus sp. compared with the control. At the end of the feeding period, the basal and glucose stimulated short-circuit current (Isc) and electrical tissue conductivity were measured in the isolated gut mucosa to characterize the electrical properties of the gut. The addition of glucose on the mucosal side in Ussing chamber produced a significant increase (p = 0.001) in Isc in both jejunum and colon relative to the basal values in Lactobacillus probiotic group. This increase in Isc for probiotic group in jejunum is equivalent to an increase of about two times that for the basal values, while in the control group is about half fold that for the basal value. In addition, the DeltaIsc after glucose addition to the large intestine was greater than the DeltaIsc in the small intestine in both control and probiotic group. Moreover in both jejunum and colon, the increase in Isc for birds fed Lactobacillus was higher than their control counterparts (p < or = 0.1). This result suggests that the addition of Lactobacillus sp. to broiler diets increased the glucose transport. Additionally, the results indicated that the conductivity of jejunal and colonic tissues remained unaffected by the dietary inclusion of Lactobacillus and support the concept that this additive enhances the maintenance and function of the epithelial barrier. In conclusion, dietary inclusion of a microbial feed additive (L. salivarius and L. reuteri) slightly increased the growth performance and improved intestinal nutrient absorption which was in association with the intestinal architecture improvement.

Campylobacter infection in chickens modulates the intestinal epithelial barrier function

Asymptomatic carriage of Campylobacter jejuni is highly prevalent in chicken flocks. Thus, we investigated whether chronic Campylobacter carriage affects chicken intestinal functions despite the absence of clinical symptoms. An experiment was carried out in which commercial chickens were orally infected with C. jejuni (1 × 108 CFU/bird) at 14 days of life. Changes in ion transport and barrier function were assessed by short-circuit current (Isc) and transepithelial ion conductance (Gt) in Ussing chambers. Gt increased in cecum and colon of Campylobacter-infected chicken 7 d post-infection (DPI), whereas Gt initially decreased in the jejunum at 7 DPI and increased thereafter at 14 DPI. The net charge transfer across the epithelium was reduced or tended to be reduced in all segments, as evidenced by a decreased Isc. Furthermore, the infection induced intestinal histomorphological changes, most prominently including a decrease in villus height, crypt depth and villus surface area in the jejunum at 7 DPI. Furthermore, body mass gain was decreased by Campylobacter carriage. This study demonstrates, for the first time, changes in the intestinal barrier function in Campylobacter-infected chickens and these changes were associated with a decrease in growth performance in otherwise healthy-appearing birds.

Impacts of the feed contaminant deoxynivalenol on the intestine of monogastric animals: poultry and swine

Deoxynivalenol (DON) is one of the most prevalent cereal contaminants with major public health concerns owing to its high toxigenic potentials. Once ingested, DON first and foremost targets epithelial cells of the gastrointestinal tract, whose proper functioning, as the first line of defence, is of paramount importance for the hosts health. Emerging evidences, summarized in this article, suggest that DON produces its toxicity primarily via activation of the mitogen‐activated protein kinases (MAPKs) signalling pathway and alteration in the expression of genes responsible for key physiological and immunological functions of the intestinal tissue of chickens and pigs. The activation of MAPKs signalling cascade results in disruption of the gut barrier function and an increase in the permeability by reducing expression of the tight junction proteins. Exposure to DON also down‐regulates the expression of multiple transporter systems in the enterocytes with subsequent impairment of the absorption of key nutrients. Other major intestinal cytotoxic effects of DON described herein are modulation of mucosal immune responses, leading to immunosupression or stimulation of local immune cells and cytokine release, and also facilitation of the persistence of intestinal pathogens in the gut. Both of the last events potentiate enteric infections and local inflammation in pigs and poultry, rendering enterocytes and the host more vulnerable to luminal toxic compounds. This review highlights the cytotoxic risks associated with the intake of even low levels of DON and also identifies gaps of knowledge that need to be addressed by future research. Copyright

The Toxicological Impacts of the Fusarium Mycotoxin, Deoxynivalenol, in Poultry Flocks with Special Reference to Immunotoxicity

Deoxynivalenol (DON) is a common Fusarium toxin in poultry feed. Chickens are more resistant to the adverse impacts of deoxynivalenol (DON) compared to other species. In general, the acute form of DON mycotoxicosis rarely occurs in poultry flocks under normal conditions. However, if diets contain low levels of DON (less than 5 mg DON/kg diet), lower productivity, impaired immunity and higher susceptibility to infectious diseases can occur. The molecular mechanism of action of DON has not been completely understood. A significant influence of DON in chickens is the impairment of immunological functions. It was known that low doses of DON elevated the serum IgA levels and affected both cell-mediated and humoral immunity in animals. DON is shown to suppress the antibody response to infectious bronchitis vaccine (IBV) and to Newcastle disease virus (NDV) in broilers (10 mg DON/kg feed) and laying hens (3.5 to 14 mg of DON/kg feed), respectively. Moreover, DON (10 mg DON/kg feed) decreased tumor necrosis factor alpha (TNF-α) in the plasma of broilers. DON can severely affect the immune system and, due to its negative impact on performance and productivity, can eventually result in high economic losses to poultry producers. The present review highlights the impacts of DON intoxication on cell mediated immunity, humoral immunity, gut immunity, immune organs and pro-inflammatory cytokines in chickens.

Gross intestinal adaptations in relation to broiler performance during chronic aflatoxin exposure

The present trial was conducted to study some morphological, digestive, and electrophysiological variables of the small intestine during chronic exposure of broilers to aflatoxin B(1) (AFB(1)). Ross 308 male chicks (7 d old) were randomly allotted to control (no AFB(1)), low AFB(1) (0.07 mg of AFB(1)/kg), or high AFB(1) (0.75 mg of AFB(1)/kg) diet. The high AFB(1) diet resulted in reduced (P ≤ 0.002) bird performance during the first 4 wk of exposure, whereas the low AFB(1) diet temporarily reduced (P = 0.034) the bird performance during wk 3 of exposure. During wk 4 of exposure, a linear (P ≤ 0.013) decrease in the unit weight of both the duodenum and jejunum was observed with increasing levels of AFB(1). This reduction in unit weight appeared to progress from the proximal (duodenum) to the distal (jejunum) small intestine with increase in the length of exposure and was not accompanied by modulation of electrophysiological variables in jejunal epithelium. Response from amiloride, a specific blocker of epithelial sodium channel, was also similar among jejunal epithelia of birds under different treatments. Interestingly, a compensatory linear (P ≤ 0.002) increase in the length of the duodenum and jejunum under high AFB(1) diets was noted to occur during wk 4 of exposure. Thus, retention of DM and nitrogen was not negatively affected by the AFB(1) diets. These data indicate that the intestine in broilers may adapt to an ongoing dietary challenge to AFB(1).