PENGARUH LEVEL C:N RASIO PAKAN TERHADAP PARAMETER KUALITAS AIR DAN PARAMETER BIOLOGI PERTUMBUHAN UDANG VANAME (Litopenaeus vannamei) DENGAN MODEL BUDIDAYA TANPA PERGANTIAN AIR MENGGUNAKAN MOLASES SEBAGAI SUMBER KARBON ORGANIK

The main problem in developing the intensive vaname shrimp (Litopenaeus vannamei) Shrimp farming industry is the accumulation of toxic non-organic nitrogen which must be controlled by frequent water changes. This study examines a new method to reduce inorganic nitrogen, namely through the growth of heterotrophic bacteria populations. The addition of organic carbon in the form of molasses into shrimp farming ponds with a model without changing water, can produce optimal growth of heterotrophic bacteria. Molasses can increase the level of C: N ratio of feed in shrimp culture with a model without changing water. The main objective of this study was to determine the effect of the C:N ratio level of feed on water quality parameters and biological parameters of shrimp growth including feed conversion ratio. This research was carried out for two months, from Februaryto April 2023 at the shrimp hatchery in Pantai Cermin District, Serdang Bedagai Regency, North Sumatra Province. The method used in this study was the experimental method. There were five treatments tested in the study, including: (1) treatment without using molasses with a C:N ratio of feed = 6.5 :1; (2) treatment using molasses with a ratio of C:N feed = 15.0 : 1 ; (3) treatment using molasses with a C:N ratio of feed = 17.5 : 1; (4) treatment using molasses with a C:N ratio of feed = 20.0 : 1 and (5) treatment using molasses with a ratio level of C:N feed = 22.5 : 1. Each treatment had three replications. This study concluded that the level of C:N ratio of feed had a significant effect on water quality parameters and biological parameters of shrimp growth. Based on water quality parameters and biological parameters for shrimp growth including feed conversion ratio, the best treatment in this experiment was the treatment using molasses with a C:N level of feed ratio about 20.0 : 1.