Incidence of Salmonella contamination in broiler chickens in Saskatchewan.

The incidence of Salmonella contamination in ten Saskatchewan broiler flocks varying in size from 6 200 to 14 000 was investigated from February, 1977 to April, 1979. Prior to the initial chick placement, brooding equipment, feed, water and fresh litter samples were found to be free of Salmonellae. Samples obtained from the clean and disinfected processing plant equipment before the commencement of daily operation were negative except the isolation for Salmonella anatum from the fingers of the defeathering machine in flock 4. There was no evidence of Salmonella contamination in flocks 5, 6, 8 and 10. The incidence of Salmonella was lower when cloacal swabs were taken from day old chicks fasted for 48 hours than for the same groups of chicks when carcasses were blended in nutrient broth (flocks 7 and 9). The blending of such chicks appears to be a more critical test. The serotypes isolated from eviscerated birds were the same as those isolated from used litter samples. Salmonella saintpaul was isolated from a water sample at 53 days in flock 1 and the same serotype was recovered from the intestinal contents and skin of eviscerated birds. Salmonella typhimurium was recovered from the eviscerated birds and neck samples in flock 3. In flock 4, S. saintpaul and S. anatum were isolated from 13% of the eviscerated birds sampled. Salmonella thompson, Salmonella agona and Salmonella heidelberg were recovered from 61%, 5% and 1%, respectively, of the processed carcasses sampled in flock 7.

Effects of ochratoxin A on egg production, body weight, and feed intake in white leghorn hens.

Two trials were conducted to determine whether ochratoxin A (OA) or reduced feed consumption was responsible for reduced body weight and egg production in hens. In an 8 week restricted feed intake trial two groups of White Leghorn hens received amounts of non-contaminated feed similar to that consumed in a previous trial by hens fed either noncontaminated diet or one containing 4 ppm OA. A significant (P less than .05) loss of body weight was observed during the 5th and 6th weeks in the group receiving a similar amount of feed as the OA-treated group in the previous trial, indicating that reduced feed consumption might account for the loss in body weight. Since egg production was not affected, it was possible that OA may depress egg production through a mechanism that is separate from its influence on feed intake. In an organoleptic trial White Leghorn hens were offered a choice of layer feed either with or without OA added for a three week period. There was a significant (P less than .05) reduction in the consumption of OA-contaminated feed.

Effects of ochratoxin A on growth response and residues in broilers.

The effects of continuous feeding of graded levels (.5, 1.0, 2.0 ppm) of ochratoxin A (OA) for eight weeks to male and female broiler chickens were investigated. A depression in body weight gain was observed in all groups receiving OA. The depression was proportional to the level of exposure to OA and was more marked and prolonged in males than in females. Detectable residues of OA were observed in the liver and kidney of birds fed 2 ppm OA. Residues disappeared from liver within 24 hr and from kidney within 48 hr after withdrawal of the mycotoxin from feed. No residues of OA were found in muscle or fat.

Absorption of dietary beta-sitosterol in laying hens and its incorporation into the egg.

Studies were undertaken to determine the dietary beta-sitosterol absorption in laying hens and its incorporation into the egg. Hens were divided into four groups and fed a commercial low-fat laying diet. Group 1 served as controls; the diet of group 2 was supplemented with 10% corn oil; group 3 with 4% plant sterols (emulsion in carboxymethylcellulose); group 4 with 10% corn oil and 4% plant sterols. The daily beta-sitosterol intake of hens in groups 1, 2, 3 and 4 was 0.036 g 0.095 g, 2 g and 2.56 g, respectively. After consuming the diets for 30 to 40 days, cholesterol and beta-sitosterol contents of the eggs were estimated by gas liquid chromatographic and mass spectrometric methods. Feeding corn oil with and without plant sterols increased cholesterol content of the eggs, while feeding plant sterols alone had no effect on egg cholesterol levels. The beta-sitosterol content of eggs from groups 1 and 2 was similar (60-66 mug/g yolk) and feeding plant sterols increased the beta-sitosterol content to a very small extent (82-90 mug/g yolk). Studies on the dietary beta-sitosterol and cholesterol absorption indicated that there was very little absorption of beta-sitosterol. In control hens, beta-sitosterol absorption was about 7% compared to 81% cholesterol absorption. Plant sterols feeding did not affect the beta-sitosterol absorption but reduced cholesterol absorption by 40%. Feeding corn oil alone did not affect cholesterol absorption. Failure to detect any significant amount of beta-sitosterol in these hens. At the peak radioactivity deposition in the eggs, only 2% of the absorbed beta-sitosterol radioactivity was found in the eggs of group 4 compared to 5% found in group 1, while cholesterol radiioactivity was nearly 4 to 5 times in both groups. These data suggested that laying hens synthesized specific lipoproteins for deposition in yolk.

Pathological changes in chickens, ducks and turkeys fed high levels of rapeseed oil.

Rations containing 25% of either regular rapeseed oil (36% erucic acid), Oro rapeseed oil (1.9% erucic acid), soybean oil or a mixture of lard and corn oil were fed to chickens, ducks and turkeys. The regular rapeseed oil ration caused growth depression, increased feed conversion and anemia in all species. All the ducks and some of the chickens fed the regular rapeseed oil ration died. These dead birds were affected with hydropericardium and ascites. No deaths in the turkeys could be attributed to the regular rapeseed oil ration but some turkeys fed this ration had degenerative foci characterized by infiltrations of histiocytic and giant cells in the myocardium. Severe fatty change in the heart, skeletal muscles, spleen and kidney was found at an early age in all birds fed the regular rapeseed oil ration. Less severe fatty change but no other lesions were found in birds fed the Oro rapeseed oil and soybean oil rations.

Acute oral ochratoxicosis in day-old White Leghorns, turkeys and Japanese Quail.

The comparative acute, oral toxicity of ochratoxin A for three day-old avian species is presented. The seven-day LD50 value for White Leghorns was calculated to be 3.4 +/-0.19 mgm./kg., for turkeys to be 5.9 +/- 0.72 mgm./kg., and for Japanese quail to be 16.5 +/- 0.56 mgm./kg., body weight. The dose-response curves are linear and parallel through one standard deviation on either side of the LD50 when log-dose is plotted against probit for survivors. It is suggested that the mechanism of action of ochratoxin A is similar in the three species, though the potency differs. The reduction in weight gain of Leghorn survivors was proportional to dose, and was observed in two separate traials over an overall dosage range from 0.2 mgm./kg. to 5 mgm./kg. The turkeys showed only a slight reduction in weight gain at doses less than 4mgm./kg., a more marked reduction being observed at higher dose levels. The quail did not show reduction of weight gain at dose levels below 10.9 mgm./kg., though the reduction was proportional to dose at higher levels. All birds dying of acute ochratoxicosis revealed a progression of symptoms from listlessness, huddling, occassionally diarrhoea, ataxia, prostration and death. Viscereal gout was observed at necropsy of the Leghorns.