1.
Pathogenesis Of Aflatoxin B1 In Quails Under Experimental Conditions And Detoxification By Biological And Chemical Means
by Sakhra Mahmood (2005-VA-251) | Prof. Dr. Muhammad Younus Rana | Prof. Dr. Asim Aslam | Prof. Dr. Aftab Ahmed Anjum.
Material type: ; Literary form:
not fiction
Publisher: 2016Dissertation note: Secondary metabolites of certain fungi produce toxins under favorable conditions especially while growing on different food grains. Mycotoxins are among major threats to growing poultry industry and human beings. Aflatoxins are closely related, biologically active fungal metabolites and commonly produced by Aspergillus species.
A research was carried out to evaluate the ability of Aspergillus flavus for Aflatoxin B1 production using rice, wheat and maize as substrates. Lethal effects on growth performance parameters, hematological and histopathological of graded doses of aflatoxin B1 in quails under experimental conditions were observed. Effect of Aflatoxin B1 on humoral immune response to Newcastle Disease virus vaccine in quails were determined. Biological detoxification of Aflatoxin B1 by Saccharomyces servisiae was evaluated in quails. Comparative evaluations of different commercially available toxin binders were checked. All these experiments were carried out till the six weeks (42 days).
Aspergillus flavus was identified on the basis of macroscopic and microscopic characteristics. Rice, wheat and maize grains was used as substrate to check the level of Aflatoxin B1 produced by inoculating an aqueous suspension of 106 spores/ml. Aflatoxin B1 checked by Thin Layer Chromatography (TLC) and quantified by High Performance Liquid Chromatography (HPLC).
Quails were reared under standard management conditions in five groups (A, B, C, D and E) having sixty each. Each group was further divided in two independent units. Diets offered to groups were control (without toxins), 0.25, 0.50, 1 and 2 mg Aflatoxin B1/kg feed. One unit of
SUMMARY
187
each group was vaccinated with Newcastle Disease Virus (NDV) vaccine while other was not and studied the lethal effects on growth performance, blood parameters, immune response and histopathology of vital organs. At the end of the experiment, it was found that the deleterious effects of Aflatoxin B1 were dose and duration dependent. As the level of the toxin was increased, the lethal effects were prominent. The growth performance parameters including gain in body weight, feed intake and feed conversion ratio was adversely affected at high doses. The body weight gain was significantly reduced in Aflatoxin B1 treated groups as compared to control group. Similarly feed intake and feed conversion ratio were significantly different from the control group. The hematological studies exhibited that aflatoxin B1 significantly reduced the hemoglobin, packed cell volume and total leukocyte count whereas the erythrocyte sedimentation rate was significantly increased as compared to control group. The immune response against NDV vaccine was adversely effected in Aflatoxin B1 treated groups and values of Antibody titer in AFB1 were significantly low as compared to group A( control) In the second experiment, Saccharomyces cervisae (SC) dried powder was mixed in basal quail diet having 0.5mg Aflatoxin B1 for all experimental groups and control was without toxins. SC was added at levels of 0.5 gm, 1.0 gm and 2.0 gm /kg of feed. It was recorded that Saccharomyces cervisae (yeast) have the potential to remove the deleterious effects of Aflatoxin B1. Yeast effectively detoxified the Aflatoxin B1. The results recorded of growth performance and other parameters were non-significantly different from the control group. Chemical detoxification of Aflatoxin B1 was evaluated in quails using commercially available toxin binders. Toxin binders used were activated charcoal, kaoline, Myco AD and selenium plus vitamin E and mixed in basal quail diet having 0.5mg Aflatoxin B1 for all experimental groups and control was without toxins. The Myco AD and selenium plus vitamin E showed the highest detoxification potential as compared
SUMMARY
188
to other chemical toxin binders. Groups E and F showed the results of growth performance, hematological, immune response and histopathological were non-significantly different from the control group (A). Kaolin was moderately detoxifying the toxin.
Presence of aflatoxin B1 in soft tissues was checked by TLC and quantified using HPLC. The liver exhibited the residues of Aflatoxin B1 at high doses of toxin. Group D and E rearing on feeds having 1mg AFB1 /Kg feed and 2mg AFB1 /Kg feed of toxin showed the residues of AFB1 in liver and kidney.
Statistical means for growth performance parameters, hematological, immune response and histopathological scores in each subunit of quails were analyzed by applying one way ANOVA and Duncans‟s Multiple Range (DMR) test at 95% probability. Aflatoxin B1 is lethal and lowers the performance of birds. The lethal effects can be detoxified by biological and chemical means to lower the economic losses to poultry industry. It can be concluded that biological detoxification is preferably better as compared to chemical detoxification. Availability: Items available for loan: UVAS Library [Call number: 2670-T] (1).
2.
Effect Of Bacillus Subtilis And Sodium Butyrate On The Morphometry Of The Small Intestine And Immune System In Healthy And Salmonella-Challenged Broiler Chickens
by Arbab Sikandar (2005-VA-154) | Dr. Hafsa Zaneb | Prof. Dr. muhammad Younus | Dr. Sima Masood | Prof. Dr. Asim Aslam.
Material type: ; Literary form:
not fiction
Publisher: 2017Dissertation note: Supplementation ofBacillus subtilis and microencapsulated sodium butyrate in the feed is being practiced as a substitute for antibiotics growth promoters. An expansive range of encouraging health-related properties exhibited by B. subtilis and SB has been published, but their exact effect on gut and immune system is not completely understood. Consequently, the evaluation of B. subtilis andSB as feed supplements is desired. To achieve this goal, the present study was aimed to investigate the effects of B. subtilis and SB on performance, immune system, gut and lymphoid organs microarchitecture in healthy and Salmonella-challenged broiler chickens.
In the first experiment the research was targeted to investigate the effects of B. subtilis on performance, immune system, gut and lymphoid organ microarchitecture in broilers. A total of 120 d-old broiler chicks were randomly distributed into four groups, each group with three replicates containing 10 birds per replicate. The birds were fed a corn-soy-based basal diet (BD, control) or BD supplemented with 10% zinc bacitracin (ZnB), and 0.05g/kg or 0.1g/kg of B. subtilis, respectively. On d 21 and 35, six birds from each group were killed to collect blood and visceral organs (thymus, spleen, bursa of Fabricius, liver and small intestine). Parameters evaluated included growth performance, immune responses, relative organ weights, lymphoid organs and gut mucosal morphometry, intraepithelial lymphocytes (IEL) count and goblet cell histochemistry in mucosa. Results showed that the group fed 0.1g/kg of B. subtilis had superior (P<0.05) mean body weight and weight gain, and lower FCR compared to the non-supplemented or ZnB-fed groups.The BS-0.1 group revealed higher antibody titer against Newcastle disease (ND) virus and the supplemented groups against sheep RBCs (SRBCs) on d 35. Cell-mediated immune response post-phytohemagglutinin-P injection was attained (P<0.05) by birds in the BS-0.1 group at 24h, and by both the BS-0.1 and BS-0.05 groups at 48 and 72h compared to the ZnB and control groups. The BS-0.1 group gained higher (P<0.05) relative bursal weight on d 21 compared to the other groups. Compared to the control group, the liver, spleen and thymus weighed more (P<0.05) in the experimental groups on d 35. The histomorphological study revealed increased (P<0.05) thymus cortical width, and cortex/medulla ratio in the BS-0.1 group compared to the control. The area of the bursal follicles and germinal centers of the spleen also improved (P<0.05) in the BS-0.1 group compared to the control. Compared to the ZnB and control, higher (P<0.05) villus height, villus surface area and villus crypt ratio of the duodenum and jejunum were recorded on d 21, and higher (P<0.05) villus heightof the duodenum and ileum was noted on d 35 in the BS-0.1 and BS-0.05 groups. The number of goblet cells having acid mucin was significantly higher in the ileal mucosae of the BS-0.1 group chickens compared to the ZnB and control. In conclusion, B. subtilis type probiotics effectuated better growth performance, improved immune system and modulated morphology of lymphoid organs and gut mucosa in broilers.
The second experiment was carried out to evaluate the effects of sodium butyrate on growth performance, immune status, organ weights and the microarchitecture of lymphoid organs and the small intestine compared to the effects brought about by an antibiotic. The cell-mediated immune response at 48 h post-phytohemagglutinin-P injection, and antibody titer against NDV and sheep RBCs on d 35 was higher (P < 0.05) in SB-1 chicks compared to those in the ZnB and control groups. Higher (P < 0.05) weight gain, and lower (P < 0.05) FCR were attained by the supplemented groups compared to the control. The thymus and spleen weighed more (P < 0.05) in the SB-1 group and bursa registered more (P < 0.05) weight in both SB groups compared to the control. On d 21, areas of the thymus medulla and the spleen germinal centers were larger (P < 0.05) in SB-1 chicks compared to ZnB and control chicks. The VH and VSA increased (P < 0.05) in the duodenum and jejunum in both SB groups on d 21, and in SB-1 on d 35 compared to the ZnB and control groups. The villus to crypt ratio was higher (P < 0.05) in the duodenum in SB-1 chicks compared to ZnB and control chicks. On d 35, VH in all segments and VSA in the duodenum and jejunum increased (P < 0.05) in SB-1 chicks compared to ZnB and control chicks. Statistically, IEL count was not significant among supplemented groups. On d 21, the number of goblet cells containing acidic mucin increased (P < 0.05) in all the segments of the small intestines in the SB-1 group compared to the control group and on d 35 in the ileum compared to the other groups. In conclusion sodium butyrate elicited better growth performance, improved immune system and modulated the morphology of lymphoid organs and the gut mucosa in broiler chickens.
The third experiment was focused to assess the effect of B. subtilis and SB on gut development, growth performance and immune system in broilers challenged with S. Gallinarum. Better growth performance was reported in the supplemented groups compared to the NC-S group due to better feed efficiency. The B. subtilis-supplemented group exhibited higher (P < 0.05) cellular immunity and antibody titer against NDV compared to the PC-S and NC-S groups. Furthermore, B. subtilis¬- and SB-supplemented groups reflected higher (P < 0.05) relative thymus and bursa weights, and improved microarchitecture of the lymphoid organs compared to the NC-S group. On d 21, villus surface area in the jejunum and ileum increased (P < 0.05) in sodium butyrate-treated birds. The crypt depth of the jejunum decreased (P < 0.05) in B. subtilis and sodium butyrate groups compared to NC-S and PC-S groups. On d 35, the villus height, villus surface area and VH:CD ratio of the duodenum increased (P < 0.05) in the supplemented groups compared to the NC-S group. The FCR, Salmonella population in ceca and mortality were higher (P < 0.05) in the NC-S group. In conclusion, the prophylactic use of the B. subtilis probiotic and SB alleviated stress associated with SalmonellaGallinarum infection and improved performance, immune function, lymphoid organs and gut mucosal development in infected broilers. Further analyses are needed to reveal the mechanism(s) by which B. subtilis and sodium butyrate produce such effects.
Availability: Items available for loan: UVAS Library [Call number: 2790-T] (1).
