Muscles from 12 moderately or heavily infected hogs contained relatively large amounts (0.25 to 13.70 Atg/g) of n-valerie acid, an acid rarely found in vertebrate tissues. The n-valeric acid content in general, correlated well with the larval counts in the diaphragm, tongue, and psoas musclescorrelation coefficients of 0.81, 0.84, and 0.82, respectively, were obtained. Only trace amounts of the acid were found in the visceral organs of the infected hogs. Trace amounts were also found in the muscles and organs of hogs with infections of less than 21 days duration, in hogs with no known helminth infections, and in hogs with ascaridand kidney worm-infections. The level of n-valeric acid in infected muscle per larva counted was about twice that per decapsulated larva or per isolated cyst from the same muscle. The production of the volatile fatty acid, n-valeric, in animal metabolism is evidently uncommon (Bueding and Most, 1953; von Brand et al., 1952). Bacteria and molds produce this acid (bacteria, Barker and Haas, 1944; Bornstein and Barker, 1948; Dehority et al., 1958; Nakae and Elliot, 1965; Yoshiaki and Karashimada, 1966; Serzedello, 1967; molds, Leal et al., 1966; Nishibe et al., 1966). Consequently, it occurs in swine feces where the diet controls its proportion among the volatile fatty acids (Friend et al., 1962). In the parasitic helminths, this acid was probably first observed by Bunge (1889) when he was studying anaerobic fermentation in Ascaris lumbricoides and A. megalocephala (= Parascaris equorum). Bunge found that the products of the fermentation process were CO2 and a strong-smelling, volatile fatty acid that he did not identify. Weinland (1901, 1902, 1903), with objectives similar to those of Bunge and using the same nematodes, identified the strong-smelling component as valeric acid and as a major end product of carbohydrate metabolism. Later, other isomers of valeric acid and other fatty acid components were identified in A. lumbricoides (Bueding and Yale, 1951; Bueding, 1953). In in vitro studies concerning carbohydrate metabolism of the larvae of Trichinella spiralis, von Brand et al. (1952) found n-valeric acid to be a major end product. The present work was undertaken to determine if n-valerie acid could be detected in Received for publication 10 October 1969. certain muscles and organs of trichinous hogs to ascertain if such a determination could be used to diagnose trichinosis in swine. MATERIALS AND METHODS The larvae and cysts of Trichinella spiralis utilized in this study were obtained from hogs infected with a strain of the parasite that had been maintained in swine at this laboratory for more than 30 years. In all experiments, each hog to be infected was fed trichinous pork at the rate of 500 larvae per pound of live body weight. The experimental animals were fed a well-balanced mash feed and, in some cases, shelled corn. Experimental animals All experimental hogs were raised worm-free until weaned, in concrete pens that were washed daily, as recommended by Spindler (1942). The 11 noninfected controls as well as 10 of the 15 infected hogs were maintained in such pens until slaughter; 5 of the infected hogs were maintained in a fenced hog lot. Spot checks at slaughter for trichurids and asearids in the controls and experimentally infected trichinous hogs were negative. The duration of the infections in the 15 infected hogs ranged either from 45 days to 8 months or from 11 to 20 days. Also, 3 ascaridand 2 kidney worm-infected pigs, which were used in other experiments, were used as helminth-infected, nontrichinous controls. At necropsy, the hogs weighed from 95 to 400 lb. Preparation of tissue samples The following tissue samples were taken from each of the 15 infected and 11 control hogs at slaughter: diaphragm (pillars), tongue, psoas, intercostals, loin, heart, duodenum, liver, and kidney. The samples were washed and ground separately in an electric food chopper. The ground samples of each tissue were well mixed and 2 or 3 10-g portions removed within 3 hr after the death of the donor, and processed for examination
Read full abstract
Jun 1, 1984
Yuzuru Yamamoto + 6
Open Access
