Stomach pH, feeding rhythm and ingestion rate in Oreochromis niloticus L. (Pisces: Cichlidae) in Lake Awasa, Ethiopia

Hydrobiologia ◽  
1989 ◽  
Vol 174 (1) ◽  
pp. 43-48 ◽  
Author(s):  
T. Getachew
Keyword(s):  
Oreochromis Niloticus ◽  
Ingestion Rate ◽  
Feeding Rhythm ◽  
Stomach Ph

scholarly journals Diel Feeding Rhythm and Grazing Selectivity of Small-Sized Copepods in a Subtropical Embayment, the Northern South China Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Xuejia He ◽  
Ziyu Wang ◽  
Ziqing Bai ◽  
Liuyu Han ◽  
Mianrun Chen
Keyword(s):  
Ingestion Rate ◽  
Northern South China Sea ◽  
Standing Stock ◽  
Feeding Preference ◽  
Daya Bay ◽  
Pigment Analysis ◽  
Feeding Rhythm ◽  
Feeding Rhythms ◽  
Gut Pigment ◽  
Diel Feeding Rhythm

Small marine copepods are key components of the pelagic food webs in Chinese coastal waters, but very few studies have addressed their trophodynamics, with even fewer studies addressing their diel feeding rhythms. In this study, the diel feeding rhythm and grazing selectivity of the copepod assemblage in Daya Bay during September 30 to October 2, 2014, were studied based on gut pigment analysis. Small copepods (body length < 1.5 mm) including Paracalanus parvus, Temora turbinata, Acrocalanus gibber, Temora stylifera, Euterpe acutifrons, and Acrocalanus gracilis, accounted for 73.9–100% of the total copepod abundance. The copepod assemblage generally exhibited a diurnal feeding pattern, characterized by a higher gut pigment content and ingestion rate during the daytime, consistent with variation in the ambient Chl α concentration. Fifty-five percent of the phytoplankton standing stock per day was consumed by the copepod assemblage, wherein diatoms, prymnesiophytes, and cyanobacteria were the main prey items with average contributions of 19.4–32.9% to the gut pigment contents. The copepod assemblage showed a strong feeding preference for prymnesiophytes, a weak feeding preference for diatoms, and avoidance of cyanobacteria. These results suggest a strong top-down control on phytoplankton community, especially on small groups from small copepods in the Daya Bay ecosystem.

Ultrastructure of Testicular Spermatozoon of the Fish Oreochromis Niloticus

1988 ◽  
Vol 46 ◽  
pp. 278-279
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Electron Microscope ◽  
Oreochromis Niloticus ◽  
Osmium Tetroxide ◽  
Sperm Cells ◽  
Adult Fish ◽  
Testicular Sperm ◽  
Thin Sections ◽  
Important Fish ◽  
Testicular Spermatozoon ◽  
Diamond Knife

Tilapia, Oreochromis niloticus, is an economically important fish in Saudi Arabia. Elucidation of reproductive biology of this species is necessary for successful breeding program. In this paper we describe fine structure of testicular sperm cells in O, niloticus.Testes from young adult fish were fixed in gluteraldehyde (2%) and osmium tetroxide (1%), both in cacodyl ate buffer. Specimens were processed in the conventional way for electron microscopy and thin sections of tissues (obtained by cutting the blocks with a diamond knife) were stained by ura- nyl acetate and lead citrate. These were examined in a Carl Zeiss electron microscope operated at 40 kV to 60 kV. Sperm cells were obtained from testes by squeezing them in cacodyl ate buffer. They were fixed in gluteraldehyde (2%) in the same buffer, air dried, gold coated and then examined in a Philips scanning electron microscope (SEM) operated at 25kV.The spermatozoon of O. niloticus is consisting of head, midpiece and tail (Fig. 1).

Ultrastructure of primary spermatocyte in fish (Tilapia: Oreochromis niloticus): The synaptonemal complex

1986 ◽  
Vol 44 ◽  
pp. 288-289
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Oreochromis Niloticus ◽  
Short Communication ◽  
Primary Spermatocyte ◽  
Mitotic Division ◽  
Meiotic Cell ◽  
Electron Microscope Level ◽  
Homologous Chromosomes

The Primary Spermatocytes represent a stage in spermatogenesis when the first meiotic cell division occurs. They are derived from Spermatogonium or Stem cell through mitotic division. At the zygotene phase of meiotic prophase the Synaptonemal complex appears in these cells in the space between the paired homologous chromosomes. Spermatogenesis and sperm structure in fish have been studied at the electron microscope level in a few species? However, no work has yet been reported on ultrastructure of tilapia, O. niloticus, spermatozoa and spermatogenetic process. In this short communication we are reporting the Ultrastructure of Primary Spermatocytes in tilapia, O. niloticus, and the fine structure of synaptonemal complexes seen in the spermatocyte nuclei.

Efektivitas Penggunaan Asam Formiat Dan Propionat Pada Pembuatan Silase Darah Terhadap Nilai Kecernaan Tepung Darah Pada Ikan Nila (Oreochromis niloticus)

2016 ◽  
Vol 2 (2) ◽  
pp. 63
Author(s):  
Rosmawati Rosmawati ◽  
Reza Samsudin
Keyword(s):  
Oreochromis Niloticus

Penelitian ini bertujuan untuk mengetahui dosis asam formiat dan propionat yang tepat pada pembuatan silase darah yang dapat meningkatkan kecernaannya pada ikan nila (Oreochromis niloticus). Rancangan percobaan pada penelitian ini adalah Rancangan Acak Lengkap dengan 6 perlakuan dan 3 ulangan. Perlakuan yang diberikan adalah perlakuan kontrol (Darah tanpa disilase), silase dengan dosis asam foemiat dan propionat (3:0%; 2,25:0,75%; 1,5:1,5%; 0,75:2,25%; 0:3%). Ikan yang digunakan dalam penelitian ini adalah ikan nila dengan bobot rata-rata 7,0 gram/ekor dengan padat tebar 20 ekor/akuarium. Parameter yang diamati yaitu nilai kecernaan protein, kecernaan lemak, kecernaan energi, dan kecernaan total. Hasil penelitian ini menunjukan bahwa pemberian dosis asam yang berbeda memberikan pengaruh yang berbeda nyata (P<0,05) terhadap nilai kecernaan protein, kecernaan lemak, kecernaan energi, dan kecernaan total pada ikan nila. Perlakuan pemberian silase dengan dosis asam formiat dan propionat 1,5:1,5% dapat meningkatkan nilai kecernaannya pada ikan nila, dengan nilai kecernaan protein 94,66%, kecernaan lemak 88,71%, kecernaan energi 92,58%, dan kecernaan total 90,27%.Kata kunci : Silase darah, Asam formiat dan propionat, Kecernaan, Ikan Nila

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