Allowable Ammonia for Fish Culture

Abstract

A review of the published literature on effects of ammonia on fish indicates that un-ionized ammonia alone is probably not the cause of gill hyperplasia, indicative of, or previously attributed to, chronic ammonia poisoning. The maximum safe concentration of un-ionized ammonia is unknown, but in many cases it is not close to the 0.0125 mg/L value commonly accepted by fish culturists.There is confusion concerning the sublethal, chronic effects of ammonia exposure on fish. In this review I attempt to point out important contributions, as well as contradictions, in the literature. The safe or acceptable levels of ammonia suggested for fish culture are at best questionable, and at worst misleading, for three reasons. First, the commonly accepted maximum safe concentration of ammonia, based on gill histology (hyperplasia of epithelium), has recently been directly and repeatedly contradicted by published empirical data. There is great variation, diurnally and hourly, in ammonia excretion rates due to differences in diets and feeding regimes, and different methods of predicting ammonia levels, based on diets and feeding, produce answers that vary by several fold. Thus a predicted ammonia production rate, calculated from literature examples for an unstudied rearing system, may not be near the actual value. And third, evidence based on studies of acute and chronic ammonia effects indicates that the effects of total metabolites cannot be predicted on the basis of only the concentrations of un-ionized ammonia. Researchers have used various methods inreporting the form and unit of measurement of ammonia. In this review un-ionized ammonia is represented as NH3, the ionized form as NH4 +, and that sum referred to as ammonia. Concentrations are reported in terms of nitrogen, and reviewed data not in this form were converted by multiplying by the appropriate factor (NH3-N = 0.8235 NH•). Allowable Concentration Guidelines Colt and Armstrong (1981) reviewed effects of nitrogen compounds on aquatic animals and noted that sublethal effects were often reported exclusively as the effects of un-ionized Prog. Fish-Cult. 47(3), July, 1985 135 weight of fish that would produce an NH•-N concentration of 0.0125 mg/L. Westers (1981)proposed such a computation and developed a practical loading formula. However, use of the NH•-N concentration as a basis for the formula is in question, primarily because recent evidence discounts much of the work that attributes gill damage to NHs. Also, there is significant variation in reported levels of ammonia production. Moreover, other by-products of metabolism, including fecal solids, bacterial solids, and yet undiscovered toxic metabolites, cannot be ignored (Colt 1978) as factors that may contribute to tissue damage attributed to ammonia. Contradictions in Reported EffectsSmart (1981) reviewed the "safe" levels of ammonia and noted some contradictions. Smart compared the EPA criteria (Willingham et al. 1979) with the finding of Schulze-Wiehenbrauck (1976), that NH3-N concentrations of up to 0.13 mg/L we...

Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish

“…The acute and chronic toxicities of ammonia have been extensively reviewed for freshwater fishes (Wang & Walsh, 2000;Biswas et al, 2006;Reddy-Lopata et al, 2006). High levels of ammonia cause stress and produce harmful physiological response such as osmoregulatory disturb, kidneys and branchial epithelium damages (Meade, 1989;Soderberg, 1994), retarded growth, inefficient immune response (Cheng et al, 2004;Pinto et al, 2007) and reduced survival (Jobling, 1994). The findings in the current experiments indicated 100% survival of the fish in 96-h exposure to the control and 0.9-mg/L of total ammonia, while 98, 88, 85, 62, 30 and 25% of the fish survived to 1.4, 8.5, 13.1 18.6, 23.7 and 35.6 mg/L of total ammonia (or 0, 0.022 0.032, 0.19, 0.23, 0.31, 0.44 and 0.85 mg/L NH 3 ) respectively.…”

Effect of stocking density on water and soil quality, growth, production and profitability of farming Indian major carps

“…The values of nitrite-nitrogen ranging from 0.01 to 0.11 mg l -1 and nitrate-nitrogen ranging from 0.09 -0.66 mg l -1 in different treatments were recorded which were within safe levels (Meade, 1985;Banerjee and Lal, 1990;Lyssenko and Wheaton, 2006). Concentrations of orthophosphates were significantly lower in T1 in comparison with T2 and T3 (p<0.05), but the variations were insignificant between T2 and T3 (p>0.05).…”

“…Ammonia is toxic to fish and is considered to be a major factor limiting fish growth in intensive culture systems (Thurston et al, 1983;Cai and Summerfelt, 1992;Forsberg and Summerfelt, 1992;Leung et al, 1999). It is suggested by several researchers that the TAN values should be less than 1 mg l -1 for good growth of all aquaculture species (Meade, 1985;Jena and Das, 2006). During the present study, TAN values were found to be more than 1 mg l -1 in the treatments T2 and T3 in the months of October, November and last week of February, March and April.…”

Avaliação do potencial tóxico dos resíduos sólidos urbanos da cidade de Campina Grande - PB

“…Essa conversão promove o aumento da toxicidade no meio, e embora a concentração do nitrogênio amoniacal seja reduzido ao longo do tempo, seu efeito tóxico aumenta. Estudos realizados por Meade [18] mostram que a forma não iônica da amônia é 300-400 vezes mais tóxica do que a sua forma iônica .…”