Asian Journal of Water, Environment and Pollution, Vol. 17, No. 3 (2020), pp. 61-64. DOI 10.3233/AJW200037 Effect of Feed Supplement on Sperm Quality and Total Intestinal Bacteria of Fish Exposed by Cadmium Alfah Hayati*, Farah Annisa Nurbani, Meirizka Amira, Windy Seftiarini, Aken Puti Wanguyun and Bayyinatul Muchtaromah 1 Department of Biology, Airlangga University, Surabaya, Indonesia 1 Department of Biology, State Islamic University, Maulana Malik Ibrahim Malang, Indonesia * alfah-h@fst.unair.ac.id Received February 2, 2020; revised and accepted June 5, 2020 Abstract: In the ecological environment, cadmium, a heavy metal produced from human activities and industry toxic material, has polluted the water and affects the reproductive health of aquatic biota. Many fsh farmers use water from the river for freshwater fsh cultivation. This study examined the effects of supplementation feed (probiotics and vitamin C) on sperm quality and total bacteria in fsh intestine, Oreochromis niloticus, after Cadmium (Cd) exposure. We found that probiotics did not seem to colonise fsh intestine or change the overall amount of the intestinal microbiota. However, probiotic supplementation actually changed the total amount of bacteria in the fsh intestine. In particular, the administration of probiotics in fsh exposed to Cd has increased more intestinal bacteria compared to the administration of vitamin C. The addition of vitamin C as a supplement did not affect the total amount of bacteria in the fsh intestine. These results indicated that probiotics have a signifcant capacity to recover sperm motility in freshwater fsh exposed to Cd pollution. Key words: Fish, probiotic, sperm quality, intestinal bacteria, cadmium. *Corresponding Author Introduction Fish are nutritional sources of proteins, minerals and vitamins. During the last few decades, industrial development has resulted in heavy metals contamination of freshwaters. They can either be adsorbed or accumulated by aquatic organisms, including fsh (Hayati et al., 2017a; Sujata. 2015). Heavy metals enter the aquatic ecosystem where they pose a serious threat because of their toxicity, bioaccumulation and biomagnifcations in the food chain (Hamada et al., 2018). Industrial discharges such as coal and oil combustion are considered as the major sources of heavy metals pollutants of water. Fish absorb heavy metals from water through the digestive tract, skin and gills. The heavy metals which spread concern to aquatic biotic health are lead (Pb), mercury (Hg) and cadmium (Cd) (Rahman et al., 2018). Uptake of heavy metals through food chain in aquatic organisms may cause various disorders related to growth, reproduction rate, mortality and physiological functions (Nursanti et al., 2017; Putranto et al., 2014; Valko et al., 2006; Usman et al., 2013). Freshwater fsh are vulnerable to Cd toxicity. The toxic effects of Cd on fsh sperm can reduce the duration of motile and immotile sperm in vitro (Hayati et al., 2017b). Bacterial bioremediation could be a good alternative to remediate heavy metal pollution in water. The use of bacteria for remediation of heavy metals Cd is capable to transforming them into less toxic forms. There are several types of microbes to remediate heavy metals,