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مظهرية القناة الهضمية وعلاقتها بتغذية ثلاثة انواع من الاسماك في منطقة ابو جولانة جنوب هور الجبايش == Morphology of digestive tract in relation to feeding in three fish species in Abo - Choolana southern AL - Chebayish Marsh
Author name:
اسماء عبد الهادي صالح
Supervisor name:
عادل يعقوب يوسف الدبيكل | جاسم محسن عبد
General topic:
Agricultural sciences
Specific topic:
Zoology - Fish And Marine Wealth
Degree:
Master
University:
University Of Basrah - Faculty Of Agriculture
Language:
Arabic
University location:
Basrah
First pages:
31T1756 - p.pdf
Abstract:
Addrressed study in alimentary gut morphology and relationship feeding of three fish species with different food habits i.e. Leuciscus vorax (Shilik) as a carnivore, Planiliza abu (Khishni) as an omnivore and Oreochromis aureus (tilapia) as a herbivore and the activity of alpha - amylase enzyme. Each species was divided into two length groups : 1 - Shilik 300≥ (227 fish) and ˂300 mm (117 fish) .2 - Khishni 100≥ (508 fish) and ˂ 100 mm (706 fish) .3 - Tilapia 150≥ (270 fish) and 150 mm ˂ (309 fish) .Fish were sampled monthly during the period from February 2014 to January 2015 using cast net and an electrical apparatus. Air temperature in the study area during that period ranged between 14 and 33°C and water temperature between 12 and 32 °C, while salinity ranged between 1.42 and 2.9 ppt.Appearance of Shilik mouth was characterized by a superior position, toothless jaws and barbells. The mouth position in Khishni and Tilapia was terminal with an extension of buccal cavity. Khishni lacked mandibular teeth which related to its feeding habits, while 3 - 4 rows of teeth were existed in the lower jaw of tilapia to cut plants parts.The three fish species has four branchial arches which were different in length reflecting the respiratory and feeding needs. the average length of the first arch of Shilik for the two length groups were 34.93 and 73.42 mm, in Khishni 13.96 and 19.41 mm and in tilapia between 22.63 and 37.86 mm, respectively. Gill rakers of the three species differ in length and number to accommodate their feeding habits. The average length of gill rakers in Shilik was 1.78 and 3.78 mm, in Khishni it reached 1.09 and 4.12 mm and in tilapia were between 1.91 and 2.06 mm. The number of gill rakers differed between species and ranged in Shilik between 10 - 12 to 12 - 14, in Khishni between 45 - 55 to 62 - .55 while in tilapia 21 - 22 to 22 - 24. The pharyngeal teeth in Shilik substituted the absence of mandibular teeth and its equation was ( 5.3 - 3.5). Khishni oral cavity contain a pair of pharyngeal teeth with a rough surface helps in grinding sand and mud solid particles with a length ranged from 5.14 to 8.02 mm and a width from 3.34 to 4.78 mm. Tilapia length of pharyngeal teeth were 4.91 and 9.61 mm, and the width was 4.37 and 7.28 mm.It was possible to distinguish two gut areas in the three species depending on diameter, where the anterior was wider than posterior area. The anteriorbintestine thickness were 23.74 , 4.29 and 3.34 mm, while the posterior thickness were 7.28 , 2.42 and 1.62, respectively. These differences confirm the variations in feeding habits. The relative gut length (RGL) of Shilik was 1.11 and 1.08 mm for the two length groups with no significant correlation with the standard length. In Khishni, it was 2.79 and 3.45 mm with 7 - 9 loops and the statistical analysis did not show significant correlation with standard length.The gizzard of Khishni through which food coarse are crushed, reached a width, height and wall thickness of its wall of 8, 4.26, 2.84 and 12.24, 6.24 and 4.59 mm, respectively. Tilapia RGL were 9.50 and 10.25, respectively.The stomach contents of the studied species were examined by dissected and compound microscope, using weight percentages, points and frequency of occurrence methods to calculate the index of relative importance (IRI). The three species showed similar patterns in the feeding intensity and activity during the study period with lowest values recorded during summer and the highest during spring.Result levins index showed That individual of the Shulik were small narrow specialization (0.27) and large (0.25) highly specialized, with fishes Khushnia (0.42 and 0.37) and blu tilapia (0.32 and 0.32) and were narrow specialization of small and large individual, respectively.The results of proximate analysis showed differences in the natural food of the three species depending on the feeding habits of these fish. The moisture content and energy where(%69.47 and 26.82 kcal / gm) ,(% 52.23 and 5.08 kcal/ gm) ,(%61.25 and 5.40 kcal / g) for smaller length , while it was (%68.93 and 11.50 kcal / gm) , (%55.14 and 5.01 kcal/ gm ),( %64.75% and 6.08% kcal/ gm) for larger lengths. The percentages of ash and organic matter rated (%51.57 , 48.43 and %31.96 , 68.0 and %47.53 , 52.46) for smaller lengths and (%23.56, 76.44 and %36.75, 63.24 and %44.57, 55.41) for large lengths. Organic carbon rate was higher (1,72 and 2.94 and 1.61) during summer, winter and autumn for first length group of Shilik, Khishni and tilapia, respectively, while second length group reached higher rate (1.61 and 2.67 and 1.72) during spring and autumn in Shilik, spring, summer and autumn in Khishni, and only autumn in blu tilapia.Alpha - amylase showed an elevated enzymatic activity in herbivorous and omnivorous in comparison with carnivorous fish confirming its main function in the hydrolysis of starch molecules .
