Experimental area and duration: The investigation was carried out in the Department of Anatomy and Histology, Faculty of Veterinary and Animal Science, Hajee Mohammad Danesh Science and Technology University, Dinajpur. Livers of goats were collected from different slaughter houses of Dinajpur town for detailed histomorphological examinations during the period from 1st July, 2014 to 30 June, 2015. Non infected goat was reared in the farmer house.
Experimental animals: The experimental animals of this study were goats those submitted for slaughtering in the slaughter house. The experimental animals were two types such as- a) Black Bengal goats affected with fascioliasis b) Black Bengal goats not affected with fascioliasis
Selection of Black Bengal goats affected with fascioliasis: Black Bengal goats affected with fascioliasis were primarily selected from Butchers house by observing clinical signs and symptoms such as- Pallor of the mucous membranes and development of anaemia, emaciation and progressive loss of body condition, submandibular oedema and ascites (bottle jaw), loss of appetite, diarrhoea, ruffled hair coat, distended and painful abdomen, disinclination to move, significant effect on production etc which are tentative diagnosis of fasciolosis, confirmative diagnosis of fascioliasis was done by observing live parasites in the liver, bile duct and gall bladder of slaughtered goat. Faeces examination was done in the laboratory of Department of Anatomy and Histology to identify the eggs of Fasciola gigantica. Age of the goats were determined by dentition.
Selection of Black Bengal goats not affected with fascioliasis: Selection of Fasciola non affected goat was confirmed by faeces examination under McMASTER method which is as follows- This method is based on the principle that the eggs are floated up in a counting chamber. A special type of slide devised by McMaster is required in this technique. Two glass slides joined together and the space between them divided to form two counting chambers of 0.15ml capacity each is the McMaster slide. In this method a known volume of faeces (5 to 10g) is thoroughly suspended in a known volume (50 to 100 ml) of saturated salt solution (sp.gr. 1.2). The suspension may be strained through a 150 mm mesh sieve to remove the coarse
particles. A portion of the suspension is withdrawn with the help of a pasteur pipette or with an ordinary plastic transfer pipette, and allowed to run into the chambers of the McMaster slide. The slide is stand for 3 to 5 minutes to allow the eggs to float. The eggs in the two chambers are counted using low powers objectives (X10) and eyepiece (X10). The number of eggs per faeces may be calculated by using the following formula:
Number in one gram = (Number in two chamber/0.3)X dilution factor*
*Dilution factor = (Total volume of suspension in ml/Total volume of faeces)
Negative result i.e absence of Fasciola gigantica eggs was confirmed that goat was not infected with fascioliasis. Age of the goat was determined by dentition.
General management of goats not affected with fascioliasis: After confirmation regular anthelmintic was used to prevent the further infection up to slaughter. The goat was reared in conventional farming system. There was semi-concrete floor system for experimental goat. Surface of the floor was even bedding material. There is both natural and artificial air flow in the house. Both roughage and green grass were offered to him. Some times they were supplied Jackfruit leaves, Banana leaves, Mango leaves etc. Concentrates supplied by the farmers were rice polish, wheat bran ,anchor bran, boiled rice, broken maize, broken rice, tiloil cake, mustard oil cake, pulse husk, salt etc. Regular vaccination was done for the goat to prevent the contagious diseases.
Gross morphological examination: A total of 10 affected and 10 non affected livers along with gall bladders showing grossly visible abnormalities were collected for detailed morphological studies. The length and girth of the livers and gall bladders were measured by using measuring tape. The weight of the livers and gall bladders was measured by using digital weight machine. All the changes were noted. Incisions were given to the affected area to study the nature or the macroscopic cessions, whenever needed. The blood vessels and biliary ducts were opened with the help of scissors and forceps and the liver flukes were collected. The liver was then cut into small slices and the slices were squeezed and macerated in normal saline. After careful removal of larger debris’s the smaller ones was washed several times with normal saline until the supernatant fluid was clear. The sediment was then examined thoroughly for parasites, sometimes with the aid of a magnifying glass. The collected trematodes were washed in normal saline and distilled water for several times and preserved in glycerin alcohol solution which was composed 95 parts of 70 percent ethyl alcohol and 5 parts of glycerine. The parasites were identified in the Department of Anatomy and Histology, Faculty of Veterinary and Animal Science, Hajee Mohammad Danesh Science and Technology University. Microscopic examination During slaughter, affected and non affected livers having gross lesions were collected then preserved at 10% formalin, after that processed, sectioned and stained for histopathological studies following a standard procedure (Luna, 1968).
Statistical analysis: The data recording the study of the affected and non affected livers were tabulated and subjected to analysis. Statistical analysis of the data was done by paired t- test using SPSS 10.0 programme. The weight, length and girth between the affected and non affected livers were compared by t-test.