摘要：The reproduction ability of male has an important role in seeds production of Litopenaeus vannamei . The objective of research was to know the sperm characteristics from each rematuration period. The research conducted in Broodstock and Nauply Quality Control Laboratory, Central Pertiwi Bahari, Lampung Province on April until July 2006. Five male shrimps obtained from High Health, Aquaculture Inc., Hawaii-USA, about 39.4 ± 1.51 g in weight and 16.4 ± 0.43 cm in length. Carefull stripping was applied to release the mature spermatophore from the thelicum. The results showed that number of sperm at the first to fourth rematuration period relatively constant (33.62x10 6 - 39.7402x10 6 cell). However the number of abnormal sperm were relatively increase slightly (1.2806x10 6 to 23.3576x10 6 cell) and also the number of death sperm (0.293x10 6 to 3.92x10 6 cell) while the number of normal sperm were relatively decrease (29.1158x10 6 to 23.3576x10 6 cell). There were no changes in head size and tail lenght of the sperm from each rematuration periods. Keywords: Litopenaeus vannamei , spermatozoa, rematuration ABSTRAK Kemampuan reproduksi udang jantan berperan penting dalam pembenihan udang vaname Litopenaeus vannamei . Penelitian ini bertujuan untuk mengetahui karakteristik sperma pada setiap periode rematurasi. Penelitian dilaksanakan di Laboratorium Kendali Mutu Induk dan Naupli, Central Pertiwi Bahari, Propinsi Lampung, bulan April sampai Juli 2006. Udang jantan yang digunakan berasal dari High Health, Aquaculture Inc., Hawaii-USA, dengan ukuran berat 39,4 ± 1,51 g, panjang tubuh 16,4 ± 0,43 cm dan berjumlah lima ekor sebagai ulangan. Spermatofor dilepaskan dari telikum dengan teknik pengurutan. Hasil penelitian menunjukkan jumlah sperma relatif stabil pada empat kali rematurasi (33,62x10 6 - 39,7402x10 6 sel). Jumlah sperma abnormal dan sperma mati berbanding terbalik dengan jumlah sperma normal. Jumlah sperma abnormal meningkat dari rematurasi pertama hingga rematurasi ke empat (1,2806x10 6 ke 23,3576x10 6 sel) demikian halnya jumlah sperma mati (0,293x10 6 ke 3,92x10 6 sel), sedangkan jumlah sperma normal mengalami penurunan (29,1158x10 6 ke 23,3576x10 6 sel). Tidak terdapat perubahan ukuran kepala dan panjang ekor sperma dalam setiap periode rematurasi. Kata kunci : Litopenaeus vannamei , spermatozoa, rematurasi
