A review of pesticide residues in commercial zoo feeds

Abstract

Commercial zoo feeds are here con sidered to be complete and balanced diets consisting of natural food items (raw meat, fish, fruits, vegetables, hays, grains, dairy products, etc.) and sup plemental food items (vitamins, miner als, proteins, etc) that are processed together into a uniform, convenient-to use product made specifically for ani mals commonly found in zoological collec tions. The commercial zoo feeds avail able in the United States are listed in Table 1 along with their respective organo-chlorine=chlorinated hydrocarbon -(CH) residue contents. Commercial feeds used by zoological parks, but which are made specifically for labora tory animals, farm animals, or pets are not included. Of the 23 feeds listed in Table 1, only 6 have been analyzed for pesticide residues; and these only for the common CH compounds (DDT, DDE and DDD). Of the 6 feeds that were analyzed, the Hall wood Carnivore Diet, Primate Diet and Omnivore Diet, as well as the Albers Pinni-Poi Diet, were analyzed by the Georgia Department of Agriculture as part of this study. The Hill's Bird of Prey Diet was analyzed by an indepen dent laboratory for Hill's Division Ri viana Foods. The Reliable Protein Pro ducts Pinni-Fare Diet was analyzed by the GHT Laboratories of Imperial Valley, Inc., Brawley, California. Although not included in this study, it should be mentioned that the Ralston Purina Com pany monitors its own Laboratory and Special Chows for chlorinated hydrocar bons to a minimum level of 0.05 ppm and have not yet detected any CH. The methods used to detect these pesticide residues are given in the U.S.Food and Drug Administration's PESTICIDE ANALY TICAL MANUAL. For a classification of pesticide chemicals refer to Benson(1969). The organochlorine residue levels given in Table 1 for the 6 analyzed feeds may be considered low. Three probable reasons for this are: a) the natural and supplemental food items used as ingredients in the feeds may have low residue levels to begin with, b) the act of processing these feeds may further reduce the residue levels (Duggan, Barry and Johnson 1966), and c)the feeds are low in fat content (pesticide residues being concentrated in fat). For these same reasons, the feeds from Table 1 that have not yet been analyzed should also be low in CH residues. The following incidents have al ready occurred in zoos. The Hogle Zoological Garden had 3,000 pounds of Mackeral condemned by the U. S. Depart ment of Agriculture due to high levels of pesticide residues in the fish. Food items fed to the animals at the Jerusalem Biblical Zoo in Israel, as well as the periotoneal fat of those zoo animals, were found to be high in CH pesticide residues (Miller-Ben Shaul 1971). Also in Israel un hatched eggs of the long-legged buz zard, Buteo rufinus were found to con tain 12.2 ppm organochlorine pesticide residues (Mendelssohn and Marder 1970). Many more incidents such as these will undoubtedly occur as zoological park personnel become more proficient at detecting pesticide residue accumu lations in their animals' diets and body tissues. Those animals that should be affected the most by pesti cide residue accumulation should be those with a fish, meat and/or poultry diet. According to Duggan et. al. (1971), fish meat and poultry contri buted 352 of the total CH pesticide residue content for 12 classes of food. Dairy products contributed 152; fruit contributed 152; garden fruit con tributed 102; grain and cereal contri buted 102; potatoes, leafy vegetables, * 1400 N. W. 9th Street, Dania, Fia.33004