Ammonia problem in Poultry Houses Strategies for its control
M.V.LN. Raju, M.M. Chawak and S.V.R. Rao
Modem intensive poultry fanning calls for careful management of in house environment as the gaseous end/byproducts of various physiological and biochemical reactions involving birds and other organic materials, gets accumulated and create serious manage mental problems. Among them, ammonia (NH.) is the most frequently encountered toxic agent in poultry houses. It is the principal end product of microbial breakdown of litter uric acid and its concentrations inside poultry houses generally remain below a level of 25 ppm under good manage mental conditions.
However, factors like attempts of reducing ventilation to conserve heat during winter (Anderson et al; 1964), reuse of old litter Or use of same litter for a long time (Reece et al; 1979) and poor litter management often lead to accumulations of NH3 well above this level and concentrations up to 75-100 ppm are commonly found in many poultry houses (Charles and Payne, 1966 a). Higher levels of litter moisture (> 25-30%), pH (>8) and temperature and presence of favorable bacteria, fungi and yeast hasten uric acid breakdown and thus increase NH3 production (Ivos et al; 1966). Poor ventilation further aggravates the problem by allowing accumulation of the produced NH3. Cage houses, particularly having broiler breeders too develop high NH3 levels, if litter is not removed frequently.
Presence of NH3 in air can be sensed by human beings from 25 ppm onwards and theconcentrations may be measured by using precision gas detector or by exposing indicator paper wetted with distilled water to atmosphere for 15 seconds. pH goes up from 6 to 11 as NH3 concentration rises from 0 to 100 ppm (Mourn etal; 1969).
Ill Effects of Ammonia
At higher levels, NH3 is found to depress feed consumption, body weight gain, onset of sexual maturity and egg production (Charles and Payne, 1966 b). Petkov (1966) has reported as much as 9% drop in egg production upon 2 month exposure to toxic NH3 levels. Birds showed watery eyes, closed eyelids and rubbing of eyes with wings due to irritating nature of NH3. pH of egg albumen was observed to rise, facilitating deterioration of white while egg yolk developed a deep orange color, downgrading the market value (cotterill and Nordsog, 1954).
Birds exposed to higher NH3 levels developed kerato conjunctivitis (Bullis et al; 1950), air saculitis (Quarles et al; 1970) and showed reduced respiratory rate (Charles and Payne, 1966 a) and increased susceptibility to coccidiosis (Quarles and Caveny, 1979) and various respiratory diseases like New Castle, infectious bronchitis etc. (Anderson etal; 1964, Valentine, 1964 and Mourn et al; 1969), due to damaged ciliary and epithelial lining of respiratory tract. Poor carcass quality in terms of increased breast blisters was reported in broilers by Charles and Payne (1966 a). However, hatchability is reported to be affected only at very high experimental levels, which are not observed in poultry houses (Panigrahi, 1989). Control
Various approaches have been adopted to reduce NH3 production with the basic aim of either to inhibit uric acid breakdown or to bind the released NH3.
i) Better management- the easy way out Proper maintenance of liner in good condition by avoiding housing birds at high stocking densities, prevention of cake formation by regular raking and proper water management and provision of good ventilation to remove dust, odors and moisture from air will greatly help in preventing this problem to occur.
ii) Chemical treatment of Utter - Addition of certain chemicals to litter is the common practice to obtain immediate but time bound effect. Paraformaldehyde, a mixture of polyoxymethylene glycols, disintegrate slowly and release formaldehyde gas which will chemically combine with atmospheric ammonia to produce no odorous, nontoxic and white product called hexamethylenetetramine and water (walker, 1964). The antimicrobial action f formaldehyde has the added advantage of reducing microbial populations both in air and in litter. Various workers (Seltzer et al; 1969 and Veloso et al; 1974) have added this compound in flake form to litter and observed satisfactory effect up to about 3 weeks at 3% (w/w) inclusion.
Hydrated lime and super phosphate were found to be effective at levels of about 5% (w/w) and Ikg/m 2, respectively (Cotterill and Winter, 1953 and Reece et al; 1979). These compounds are widely used owing to their cheap cost and value as fertilizer. Phosphoric acid, when sprayed on litter @ 0.4 kg/m 3 greatly reduced litter pH and inhibited NH3 production up to 3 weeks (Reeceetal; 1979).
Natural zeolites (clinoptilolite, erionite etc.) have been extensively used in Japan and US. ClinoptiloUte, when used in litter @ 5 kg/m 2, gave encouraging results (Nakaue et al; 1981). Similarly, bentonites addition to litter @ 2 kg/m 2 was found to decrease NH3 production (Majewski and Tymczyna, 1989).
Volatile fatty acids like a mixture of 60% acetic and 40% prop ionic acids were used successfully up to 3% (w/w) in litter (Parknurst et al;
1974). Further, in acute conditions, addition of antibiotics like thiopeptin @100 mg/kg may be practiced to have immediate effect (Kitai and -.Arakawa, 1979).
iii) Dietary treatment
The possible role of dietary zeolites in controlling NH3 production, in addition to their proven toxin adsorption capability and performance stimulating effect, need to be studied further in view of the scanty information, available (Mumpton and Fishman. 1977). Similarly bentonites addition to diet may also be of some use. Dietary addition of antibiotics like Zinc bacitaracin or Thiopeptin @100 mg/kg also was found to depress NH3 production from litter (Kitai and Arakawa, 1979). the urease inhibiting effect of hydroxamic acid, observed in large animals (Streeteretal; 1969)offers another great scope for its practical use in poultry rations.
Extract of Yucca schidigera, a plant commonly seen in Mexico and US is presently used widely in manufacturing commercial preparations because of its known depressing effect on NH3 production from litter (Rowland et al; 1976 and Johnston et al; 1981). Others like Sorbic acid, adipic acid, gention violet, calcium propionate, copper Sulphate, ferrous Sulphate, formic acid and benzoic acid, significantly reduced dietary microbial counts (Gwara et al; 1989; Kaczmarek et al; 1989; Brake et al; 1990 and Ramakrishna et al; 1992) and therefore, their addition to diet may have some depressing effect on litter NH3 production by lowering litter microbial counts.
iv) Microbial treatment of litter
Inoculation of litter with certain genera of microorganisms that reduce production of mycotoxins like Scopulariopsis (Forgolcs and Carils, 1962) may be extended for minimizing the flora that takes part in NH3 production.
ConclusionsProductive performance and disease resistance of chicken are drastically affected by high atmospheric NH3 concentrations. This problem may be alleviated by treating diet or litter with certain compounds that hinder the production of NH3 either directly or indirectly.