Genetic Relationship and Structural Analysis of Resident Pacific Salmon Oncorhynchus Masou in Mijiang River, China

Masu salmon Oncorhynchus masou has been listed as national second-class protected species in China, and many of its local populations have been under threats of decline because of environmental deterioration by human activity, such as habitat loss, water pollution, or dams. Genetic characteristics should be clarified in wild masu salmon population for an effective protection and recovery. In the present study, we explained genetic relationship and structure of masu salmon population in Mijaing River by sequencing the COI gene and analyzing microsatellite makers. Results of COI sequences analysis revealed 15 gene variable sites in approximately 696 bp, which defined 12 haplotypes, including some haplotypes related to geographic regions. The NJ tree indicated genetic relationship that we preliminarily inferred, that is, the masu salmon from Mijiang River belonged to the cherry salmon family (O. masoumasou). Results based on 14 microsatellite loci showed high haplotype diversity and low nucleotide diversity, indicating low genetic diversity of wild masu population in Mijaing River. The observed genetic structure was influenced primarily by bottlenecks due to overfishing and habitat loss. Since masu salmon has become highly vulnerable in China, we recommend to strengthen the protection of resident masu salmon population.

EFEK PEMBERIAN MINYAK IKAN SALMON (Oncorhynchus masou) TERHADAP PRODUKTIVITAS AYAM PETELUR ISA BROWN

AbstrakTujuan penelitian ini adalah untuk mengetahui pengaruh pemberian minyak ikan salmon terhadap konsumsi pakan, berat telur, produksi telur dan konversi pakan ayam petelur Isa brown. Penelitian ini dilaksanakan di Laboratorium Ilmu Teknologi dan Produksi Ternak Unit Ternak Unggas Fakultas peternakan Universitas Halu Oleo pada bulan November 2019 selama 1 bulan. Materi penelitian ini adalah 16 ekor ayam petelur Strain Isa brown yang berumur 8 bulan. Variabel yang diamati dalam penelitian ini adalah konsumsi pakan, berat telur, produksi telur dan konversi pakan. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap yang terdiri dari 4 perlakuan dan 4 ulangan dengan pemberian minyak ikan salmon yang terdiri dari: kontrol tanpa minyak ikan (P0), 2 kapsul/ekor/hari (P1), 4 kapsul/ekor/hari (P2) dan 6 kapsul/ekor/hari (P3). Hasil penelitian ini menunjukkan bahwa pemberian kapsul minyak ikan salmon dosis 2 sampai 6 kapsul/ekor/hari belum memberikan pengaruh nyata terhadap konsumsi pakan, berat telur, produksi telur dan konversi pakan ayam petelur Isa brown.Kata kunci: Ayam petelur, Produktivitas, minyak ikan.

Effect of estradiol on gonads development for resident form males of cherry salmon Oncorhynchus masou

Effect of estradiol on development of gonads in resident form males of cherry salmon is investigated. The fish aged 0+ with initial weight of 3.48-10.70 g were treated with the hormone for 30 days, then reared for 8 months. Estradiol was given with pelleted food in concentration of 100 mg/kg. The gonads were examined histologically during entire period of the experiment. The control group included 184 specimens (90 females, 59 anadromous males and 35 males of resident form). The experimental group of 50 females and 48 males was taken randomly in 3.5 months after the end of hormonal exposure. The fund of germ cells in gonads of the experimental group consisted only of gonias. Males of resident form were identified in 6 and 8 months after the end of hormonal exposure, they were distinguished by both size of the testes and presence of germ cells at different stages. Portion of the males of resident form was similar in the control and experimental groups — 37.0 % and 40.7 % of total number of males, respectively.