One feeding trial and two balance studies were conducted to study the effects of adding arsanilic acid or vitamin E (E) upon utilization of natural or supplemental selenium (Se) (from sodium selenite) in the diet. Eighty weanling pigs were assigned at random to eight dietary treatments in a 23 factorial design. The basal corn-soybean meal diet (containing .036 ppm Se and 6 IU E/kg) was fed alone or supplemented with .1 ppm Se (as sodium selenite) and/or 22 IU E per kilogram of diet and/or 99 ppm arsanilic acid. Selenium supplements were withdrawn 60 days, and arsanilic acid supplements 8 days, before slaughter. Selenium supplementation increased (P<.01) liver, kidney and diaphragm muscle Se concentrations, while arsanilic acid increased (P<.05) diaphragm muscle Se concentrations. Vitamin E supplements had no effect on tissue Se levels. The two balance studies concerned Se absorption and retention on low-Se diets supplemented with sodium selenite or seleniferous corn, arsanilic acid and E. A greater proportion of Se from seleniferous corn was lost in the feces and less in the urine as compared to Se from sodium selenite. Vitamin E supplementation increased Se retention from seleniferous corn by decreasing urinary and fecal Se loss. Arsanilic acid decreased Se excretion and, consequently, increased Se retention. The data suggest that discrimination against use of arsanilic acid as a feed additive in diets containing nutritional levels of natural Se or in diets supplemented with .1 ppm Se from sodium selenite for growing-finishing pigs in low-Se areas is unwarranted.
Sequential serologic analysis for Actinobacillus pleuropneumoniae was done on 240 commingled feeder swine at 1 and 21 days after purchase and at slaughter. At the beginning of the experiment, mean weight of the pigs was 18.6 kg, and the pigs were maintained to a mean slaughter weight of 109.95 kg. A fourfold increase in antibody titer against Actinobacillus pleuropneumoniae was demonstrated in 28 (12%) pigs. Mean adjusted rate of gain for infected pigs was 0.74 +/- 0.10 kg/d and 0.77 +/- 0.09 kg/d for uninfected pigs. Differences in feed efficiency were not detected between infected and uninfected pigs. Our findings suggested that 5.64 additional days are required for pigs with subclinical infection to reach market weight of 113.6 kg, compared with that for uninfected herdmates. A vaccination program to prevent subclinical infection may not be cost effective.
ABSTRACT Histamine production in tuna salads extended with textured soy protein (TSP) was evaluated. Salads were inoculated with five known histamine‐producing bacteria and held at 8°C, 24°C , and 37°C for up to 48 hr. Addition of 30% TSP to tuna salads resulted in higher initial pH and favorable growth conditions for microorganisms and histidine decarboxylase activity. Addition of 15% TSP provided an initial pH for maximal enzyme and histamine production but somewhat slower microbial growth. Tuna salad extended with either 15% or 30% TSP developed toxic levels of histamine (>50 mg/l00 g) when held at either 24° or 37°C for 6 hr. Nonextended tuna salads did not develop toxic levels of histamine even when inoculated with known histamine‐producing bacteria and held at 24° or 37°C for 48 hr.
ABSTRACT Thirty-three crossbred boars, 47 to 58 days of age, were randomly allocated to receive maize-soya bean meal diets containing 0·05, 0·15 or 0·30 mg selenium per kg. Body weights, testicular widths, and blood samples from vena cava puncture were taken at regular intervals. Libido was subjectively scored upon exposure to ovariectomized-oestrogenized gilts. Seven animals from each group were slaughtered at 9 months of age and selected reproductive structures were retrieved. Analysis of the relationships among body weight, libido and plasma testosterone levels indicated that differences ( P < 0·01) existed between treatments, as analyzed over time, but that the overall treatment effect was not significant. Testicular widths were also found to be different ( P < 0·05) over time. Values for all four criteria as measured over time were greater for boars fed 0·05 mg selenium per kg than for those fed 0·15 which were in turn greater than those fed 0·30. Post-mortem examination showed no treatment differences (1) in testis weights; (2) spermatozoan concentrations within the capita, corporea or caudae segments of the epididymis and (3) spermatozoan morphology examined within the caudae epididymis. Also testis lengths, weights, circumferences and spermatozoan concentrations were not significantly different between treatments. These results suggest that boars fed selenium at 0·15 or 0·30 mg/kg may exhibit some signs of retarded sexual development for a short period preceding the onset of sexual maturity
Two experiments involving 1,020 litters were conducted at eight research stations to determine the effects of dietary NaCl (salt) concentration during gestation and lactation on reproductive performance of sows. Primiparous and multiparous sows were fed fortified corn- or grain sorghum-soybean meal diets at 1.82 kg/d during gestation. During the winter months (December, January, February) the feeding level was increased to 2,27 kg/d. Sows had ad libitum access to diets during lactation. Dietary concentrations of added salt were .50 and .25% in Exp. 1 and .25 and .125% in Exp. 2. When more feed was fed during gestation, the salt concentrations were reduced to .40, .20, .20 and .10%, respectively, in order to maintain a constant daily intake of Na and Cl during gestation. Gestation weight gain and lactation (21-d) weight loss of the sows were not affected by dietary salt level in either experiment. In Exp. 1, lowering the salt concentration did not influence the number of pigs farrowed, but it resulted in a .05 kg/pig reduction (P < .01) in average birth weight. Average 21-d pig weights also tended (P < .19) to be lower in the low-salt group. There was a decrease in litter size from the first to the second farrowing for sows fed low salt, but not for sows fed the higher salt concentration. In Exp. 2, reducing the salt content from .25 to .125% did not alter reproductive performance. The overall ratio of males to females at birth in the population of >104 pigs was 52.3:47.7. Lower salt intakes tended to reduce the percentage of males born in both experiments, although the differences were not significant (P > .3). The results indicate that reducing the salt concentration in sows diets from .50 to .25 or .125% reduces birth weight in newborn pigs. When continued for more than one reproductive cycle, feeding less than .5% salt appears to reduce litter size at birth and weaning.
Measures of growth and serum Zn concentration were made on young growing pigs receiving a low Zn (20 ppm) basal diet supplemented with 25 or 50 ppm of Zn from either zinc oxide or metallic Zn dust from the metal smelting and refining industry. Growth was not sensitive to either source or level of supplemental Zn, but serum Zn concentration increased linearly with increases in supplemental dietary Zn from either source. Equations for the linear regression of serum Zn concentration on supplemental dietary Zn were calculated from the data on blood samples after 2 and 5 weeks of the trial. The ratio of the slope of the regression line for metallic Zn dust to that for zinc oxide was 1.30 and 1.33 for the 2-week and the 5-week data, respectively. The availability of Zn from this metallic Zn dust to young growing pigs was therefore estimated to be about 30% greater than that from zinc oxide powder.
Three selenium (Se) balance trials were conducted with young pigs to compare supplements (0.2 ppm Se) of natural Se (from seleniferous corn) vs. selenite Se, a stored selenite-glucose premix (in which some selenite had apparently been reduced to elemental Se) vs. a freshly prepared selenite-glucose premix, and a supplement of 22 IU of vitamin E (E) per kilogram of diet vs. no E supplement. The basal diets consisted of corn and soybean meal plus minerals and vitamins (except E) and contained 0.041 to 0.047 ppm natural Se. A higher proportion of Se from seleniferous corn was excreted in the feces (P < .05) and a lower proportion excreted in the urine (P<.01) as compared to Se from sodium selenite. An E supplement significantly reduced fecal Se excretion of pigs fed seleniferous corn. Selenium excretion in both feces and urine tended to be greater, and Se retention concomitantly less, on the stored selenite premix than on the premix which had been freshly prepared. Vitamin E supplementation of the freshly prepared selenite premix tended to increase both fecal and urinary Se excretion and to reduce Se retention.
