Morphological Modulation OF Broiler Organs in Response to Selenium Nanoparticles-Loaded Chitosan Under Dexamethasone Induced Stress

Abstract

Morphological modulation of broiler organs in response to Selenium nanoparticles-loaded Chitosan reared under standard management conditions Selenium nanoparticles loaded to Chitosan (SeNP-Loaded-COS) exhibit excellent stability and higher bioavailability. SeNP-Loaded-COS improves the morphological characteristics of gut, bone, muscle and immune organs. Current reseach was designed to evaluate the effects of SeNP-Loaded-COS on production performance, organ development, bone health, meat quality, and morphology of gut and immune organs in broilers reared under standard managemental conditions. The 240 one-day old chicks were randomly divided into five groups and each group was further replicated eight times (n=6/replicate). Basal diet was offered to first group (i.e. control) while the rest of the four groups were supplemented with SeNP-(0.5mg/kg),COS-(200mg/kg), SeNP+COS(0.5mg/kg+200mg/kg) and SeNP-loaded-COS-(200mg/kg) of feed respectively. On day 35, two birds were selected per replicate and sacrificed in order to collect blood and samples from small intestine, bursa of fabricius, caecal tonsils, tibia bone and pectoral muscle. Supplementation of SeNP-loaded-COS and SeNP+COS increased (P<0.05) weight gain in birds whereas feed intake(FI) and the feed conversion ratio (FCR) were reduced in birds in comparison to the control group. Supplementation of SeNP-loaded-COS and SeNP+COS had variable effects on the relative weights of viscera with a decrease (P<0.05) in the relative weight of the pancreas and an increase (P<0.05) in the relative weight (RW) of bursa and spleen in comparison to the control group. Supplementation of SeNP-loaded-COS-200mg/kg increased (P<0.05) duodenal, jejunal, and ileal, villus length, villus width, ratio of villus height/crypt depth and villus surface when compared with the control group. Moreover, this SeNP-loaded-COS-200mg/kg group also revealed increased (P<0.05) duodenal and ileal acidic goblet cell(AGC), mixed(MGC) and total goblet cell (TGC) numbers whereas in jejenum only AGC and TGC numbers were higher in comparison to the control group. Regarding intraepithelial lymphocytes (IEL), small intestinal segments revealed variable results. Supplementation of SeNP-(0.5mg/kg) increased (P<0.05) ileal IEL number whereas jejenul IEL number was lower (P<0.05) in the similar group when compared with the control group. Supplementation of birds with SeNP-Loaded-COS increased (P<0.05) the lymphatic follicle length, width, and area in the bursa and also, the lymphatic nodular length and width of caecal tonsils in comparison to the control group. Supplementation of SeNP-loaded-COS increased (P<0.05) muscle pH (24 hrs), muscle fascicle diameter, muscle fiber diameter and cross sectional area but reduced drip loss (P<0.05) when compared to the control. Supplementation of SeNP-loaded-COS increased (P<0.05) bone weight and diaphysis diameter in comparison to the control group. Furthermore, the diaphysis diameter was also higher (P<0.05) in the SeNP supplemented group in comparasion to the control. Medullary canal diameter and tibiotarsal index was higher in all supplemented groups except for COS supplementation which reduced the medullary canal diameter when compared with the control group. Supplemnation of SeNP, SeNP+COS, and SeNP-loaded-COS incersaed (P<0.05) the Se concentration in muscle when compared with control group however serum and bone Se concentration remained unchanged in among different experimental groups. Regarding Ca and P, all the supplemented groups showed an increased level in serum and tibial bone when compared to the control group. Biochemical analysis revealed that supplementation of SeNP and SeNP loaded-COS increased (P<0.05) catalase concentration in comparison to control wheras cholesterol level was decresed (P<0.05) in SeNP-loaded-COS group in comparison to the other groups. Results of bacteria count revealed an higher (P <0.05) in Lactobacillus and lower (P <0.05) in Escherichia coli counts with SeNP+COS and SeNP-loaded-COS supplementation in comparison to the control group. In conclusion, SeNP-loaded-COS supplementation improved performance, intestinal and immune organ morphology and selected meat quality and bone health parameters in broilers. Keywords: Broilers, SeNP-loaded-Chitosan, gut-histomorphometry, goblet cell, IEL, immune organs, meat quality, catalase, cholesterol. viii Morphological modulation of broiler organs in response to Selenium nanoparticles-loaded Chitosan reared under dexamethasone induced stress This study was designed to examine the effect of selenium nanoparticles-loaded chitosan (SeNP loaded-COS) on production performance, mineral retention, and development of gut, bone, muscle and immune system in broilers during dexamethasone induced stress. The 384, one-day old chicks were randomly divided into six groups and each group was further replicated eight times (n=8/replicate). Basal diet was offered to the first group of birds only (i.e. negative control), while the rest of groups received either Dexamethasone (D-15mg/kg of the diet) and served as positive control. Whereas other four groups were; SeNP-D group (SeNP 0.5mg/kg,Dexa-15mg/kg), COS-D group (COS-200mg/kg, Dexa-15mg/kg), SeNP+COS-D group (SeNP-0.5+ COS-200mg/kg+dexa 15mg/kg) and SeNP-loaded-COS-D group (SeNP-L-COS-200mg/kg, Dexa-15mg/kg). On 28th and 35th day, two birds per replicate were slaughtered and sampling was performed for hematological and biometric analysis. Tissue sections were stained with H & E and combined alcian blue and Periodic acid Schiff technique. Supplementation of SeNP-loaded-COS+DEX increased (P<0.05) body weight gain and FCR while decreased (P<0.05) feed intake in last two weeks. Results of 28th and 35th day indicated a significant increase in villus height, villus surface area and ratio between villus height and crypt depth was observed in supplemented groups in small intestine. Also, an increase (P<0.05) in thickness of muscularis externa was observed in positive control. Comparable results were observed in terms of goblet cell count where an increase in jejunal acidic goblet cells, ileal acidic goblet cells and total goblet cells was observed on 28th and 35th day. In duodenum, signifanct increase in acidic goblet cells and total goblet cells was observed only on 35th day of sampling. Jejunal intraepithelial lymphocyte number increased significantly only on 35th day in supplemented groups as compared to positive control. A significant increase in area of bursal follicles was seen on 28th and 35th day while increase (P<0.05) in lymphatic nodular area of cecal tonsils was observed only on 35th day. Thymic cortex showed a significant increase in width on 35th day. In terms of muscle traits, supplementation caused a significant decrease in drip loss percentage while increased (P<0.05) fiber density on 28th day. Similary, muscle pH, fiber diameter and their cross sectional area were increased in supplemented groups on 35th day. Similar trends were observed in bone parameters where supplementation caused a significant increase in diaphysis diameter on 28th day while bone length and weight and diaphysis diameter was increased on 35thday. Mineral analysis demonstrated an increased (P<0.05) calcium (Ca) level in muscle and tibial bone on 28th day. Contrarily, Se was increased (P<0.05) in muscle on 35th day while a positive change in Se+Ca and Ca+Phosphorous was observed in serum and tibial bone respectively. Biochemical analysis showed a decrease (P<0.05) in cortisol and cholesterol levels of supplemented groups on 28th day. In contrast, catalase activity was lower in positive control on 35th day. Lactobacillus count was increased significantly on 28th day while a significant reduction in E.coli number was observed on 35th day compared to positive control. In conclusion, SeNP-loaded-COS partially improved growth performance, gut, bone, muscle and lymphoid organs morphology, mineral retention and redox status in broilers reared under dexamethasone induced stress. Keywords: SeNP-loaded-Chitosan+Dex, gut-histomorphometry, goblet cell, IEL, immune organs, muscle integrity, catalase, minerals, Cortisol