Surveillance of Salmonella prevalence in animal feeds and characterization of the Salmonella isolates by serotyping and antimicrobial susceptibility.

This article presents the surveillance data from the Feed Contaminants Program (2002-2009) and Salmonella Assignment (2007-2009) of the U.S. Food and Drug Administration (FDA), which monitor the trend of Salmonella contamination in animal feeds. A total of 2,058 samples were collected from complete animal feeds, feed ingredients, pet foods, pet treats, and supplements for pets in 2002-2009. These samples were tested for the presence of Salmonella. Those that were positive for Salmonella underwent serotyping and testing for antimicrobial susceptibility. Of the 2,058 samples, 257 were positive for Salmonella (12.5%). The results indicate a significant overall Salmonella reduction (p≤0.05) in animal feeds from 18.2% (187 samples tested) in 2002 to 8.0% (584 samples tested) in 2009. Among these samples, feed ingredients and pet foods/treats had the most significant reduction (p≤0.05). Of the 45 Salmonella serotypes identified, Salmonella Senftenberg and Salmonella Montevideo were the top two common serotypes (8.9%). Of the 257 Salmonella isolates obtained, 54 isolates (21%) were resistant to at least one antimicrobial. The findings provide the animal feed industries with Salmonella prevalence information that can be used to address Salmonella contamination problems. Our findings can also be used to educate pet owners when handling pet foods and treats at home to prevent salmonellosis.

Effectiveness of zinc acetate injection in alleviating postweaning performance lag in pigs.

Four trials were conducted using crossbred pigs (n = 308) to determine the effects of Zn acetate injection near weaning on serum Zn concentrations and performance. In Trial 1, 78 pigs (BW of 5.1 kg and age of 18 d) were injected i.m. 3 d before weaning with either 3 mg of Zn from Zn acetate (in saline) per kilogram of BW or saline. Serum Zn concentrations were higher (P < .05) for Zn-injected pigs at 1 wk postweaning than for controls. In Trial 2, 96 pigs (BW of 7.2 kg and age of 26 d) were used to compare time of i.p. injection of Zn (weaning or 12 h postweaning) and amount of Zn injected (0, 3, or 4 mg of Zn/kg of BW). Serum Zn concentrations were higher (P < .01) in Zn-injected pigs 1 d after injections and remained higher than those in controls until after wk 2. In Trial 3 (n = 30, BW of 6.9 kg and 24 d of age), pigs that were injected with 3 mg of Zn/kg BW i.p. 3 d postweaning had lower (P < .05) ADG and ADFI and lower (P < .01) gain/feed from d 4 to d 7 postweaning than controls. Zinc-injected pigs had higher (P < .05) serum Zn concentrations at d 7. In Trial 4, 104 pigs (BW of 6.4 kg) were used in a 2 x 2 x 2 factorial arrangement of treatments: 1) regrouped 3 d before weaning or not regrouped, 2) Zn injections (3 mg i.p.) or placebo, and 3) time of injection, 2 d before or 1 d after weaning. All pigs were weaned at 23 d of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Zinc concentration in tissues and performance of weanling pigs fed pharmacological levels of zinc from ZnO, Zn-methionine, Zn-lysine, or ZnSO4.

Four trials were conducted to examine concentration of zinc in tissues and performance of pigs fed high levels of Zn from ZnO, Zn-methionine, Zn-lysine, or ZnSO4. In Trials 1 (n = 80, 28 d of age, 7.5 kg BW), 2 (n = 80, 26 d of age, 7.1 kg BW), and 3 (n = 70, 23 d of age, 5.3 kg BW), pigs were assigned either to a control diet containing 105 mg/kg of Zn and 15 mg/kg of Cu or to supplemental dietary treatments of 3,000, 2,000, or 1,000 mg of Zn/kg of diet. In all three trials, dietary sources were ZnO, Zn-methionine, Zn-lysine, or ZnSO4. The trials lasted 2 wk. In Trial 1, performance of pigs generally was not improved by feeding 3,000 mg of Zn/kg from any of the Zn sources. Serum, liver, and rib Zn concentrations (P < .01) and liver Zn concentrations (P < .05) were greater for pigs fed the high Zn diets. In Trial 2, feeding high Zn did not affect overall performance. Pigs fed the high Zn diets had greater (P < .01) serum, liver, kidney, and rib Zn concentrations. In Trial 3, there were no differences (P > .10) in ADG or ADFI, but serum and liver Zn concentrations were greater (P < .01 and .05, respectively) for pigs fed high Zn diets. Within Zn sources, serum and liver concentrations of Zn were greater (P < .05) for pigs fed ZnSO4 rather than ZnO in Trials 1 and 2. In Trial 4 (n = 72, 7.1 kg), 25-d-old pigs fed diets containing 3,000 mg/kg of Zn from feed-grade ZnSO4, reagent-grade ZnSO4, or feed-grade ZnO in a 4-wk growth trial had similar ADG and ADFI, but the gain:feed ratio was lower (P < .05) for pigs fed the reagent-grade ZnSO4. Serum, liver, and kidney Zn concentrations were lower (P < .05) for pigs fed the ZnO diet after wk 2 than for pigs fed the ZnSO4 diets, but no differences (P > .10) were observed at the end of wk 4. In summary, performance was not enhanced by feeding pharmacological levels of zinc after weaning, although serum and tissue Zn concentrations were increased. When compared with the bioavailability of Zn in ZnSO4, the bioavailability of Zn was lowest for ZnO and intermediate for Zn-lysine and Zn-methionine.

Phytase supplementation of low-phosphorus growing-finishing pig diets improves performance, phosphorus digestibility, and bone mineralization and reduces phosphorus excretion.

Two experiments using 413 crossbred growing-finishing pigs were conducted to assess the use of a commercial microbial phytase (Natuphos) in corn-soybean meal diets to improve phytate P bioavailability and thus reduce inorganic P supplementation and fecal P excretion. In Exp. 1 (n = 189), the following diets were used: 1) .50/.40% total P, respectively, for grower and finisher phases, and no phytase; 2) .40/.35% P and no phytase; 3) diet 2 plus 250 U phytase/kg; and 4) diet 2 plus 500 U phytase/ kg. The total Ca level was .58/.48% for diet 1 and .53/.43% Ca for diets 2, 3, and 4 in the grower and finisher phases, respectively. Feeding the low-P diet without supplemental phytase resulted in an overall 18% reduction in ADG (P < .05), 15% reduction in ADFI (P < .05), and 3% poorer feed efficiency (P < .08). Adding 250 to 500 U phytase/kg to the low-P diet restored ADG, ADFI, and feed conversion to levels not significantly different from and within 96% of that observed for pigs fed the adequate-P diet. The overall apparent digestibility of P was linearly (P < .01) improved with addition of 250 and 500 U phytase/kg to the low-P diet, but Ca and DM digestibilities were not affected by phytase or P level. In Exp. 2 (n = 224) the following diets were used: 1) .38/.33% total P, respectively, for grower and finisher phases, and no phytase; 2) .42/.37% P and no phytase; 3) .46/.41% P and no phytase; 4) diet 1 plus 167 U/kg phytase; 5) diet 1 plus 333 U/kg phytase; and 6) diet 1 plus 500 U/kg phytase. All diets contained .41/.36% Ca for grower and finisher phases, respectively. Pigs fed the low-P control diet grew slower (P < .01) and less efficiently (P < .10) than pigs fed diets with added P or phytase. With increasing levels of supplemental phytase or P there was a linear increase (P < .01) in ADG, digestibility of P, and digested P and a quadratic improvement (P < .05) in feed efficiency. Tenth rib mineralization based on shear force and ash were linearly increased (P < .08 to .001) as phytase or P was added to the low-P diet. There were generally no effects of P or phytase level on carcass quality. Using prediction equations derived from the response traits of ADG and P digestibility in Exp. 1 and ADG, P digestibility, and bone shear force in Exp. 2 to added phytase or P, we estimated that 500 U phytase released an amount of phytate P that was approximately equivalent to .87 to .96 g of P from dicalcium-monocalcium phosphate supplements. Fecal P excretion was estimated to be reduced 21.5%.

Effects of feeding aflatoxin-contaminated diets with and without clay to weanling and growing pigs on performance, liver function, and mineral metabolism.

Ninety-six crossbred weanling pigs (36 d of age, initial weight of 8.8 kg) were used in a three-phase study to determine the effects of feeding an aflatoxin-contaminated corn (AC) diet (922 ppb of aflatoxin B1) with and without sodium bentonite (clay) on performance, liver function, and mineral metabolism. In the nursery phase, control corn (NC) or AC was fed in corn-soybean meal diets with and without 1% clay for 6 wk. Compared with NC, AC decreased ADFI and ADG (P < .01) and increased serum activities of gamma-glutamyltransferase (P < .01) and alkaline phosphatase (P < .05). In the growing phase, 48 pigs from the nursery phase were fed NC but continued on their respective clay treatments for 5 wk. Pigs previously fed AC had higher (P < .01) ADFI and lower (P < .05) gain/feed, serum Ca, K, and glucose; ADG, other serum values, and liver minerals were not affected by treatments. In the metabolism phase, 24 barrows from the nursery phase were continued on the same corn and clay treatments for two 4-d total collections of urine and feces. Feeding AC increased (P < .05) P and Na absorption. The addition of clay lowered Mg and Na absorption (P < .01) for both AC and NC. Significant interactions for many minerals indicated that the effects on mineral metabolism were more pronounced when AC was fed. Serum and liver mineral concentrations were generally unaffected by the treatments in all phases. Feeding clay with AC results in partial restoration of performance and liver function without greatly influencing mineral metabolism.

Effectiveness of different types of clay for reducing the detrimental effects of aflatoxin-contaminated diets on performance and serum profiles of weanling pigs.

Three trials were conducted with recently weaned pigs (n = 198) to determine the effects of feeding different types of clay in conjunction with aflatoxin-contaminated diets. In Trial 1, pigs (n = 54; trial length 4 wk) were assigned to either an uncontaminated treatment (NC), 800 ppb of aflatoxin from contaminated corn (AC), or AC with one of four clays. In Trial 2 (n = 81; trial length 5 wk), pigs were assigned to NC, AC (500 ppb of aflatoxin from rice starch), or AC with one of seven types of clay. In both trials, pigs fed AC had decreased ADG and gain:feed ratios (P < .05) compared with controls. The clays differed in their ability to produce gains similar to those of controls. The clays did reduce changes in the serum measurements normally affected by aflatoxin, including albumin, total protein, gamma glutamyltransferase (GGT), and alkaline phosphatase (ALP) levels, in a manner similar to their effect on ADG. In Trial 3, pigs (n = 63) were assigned to one of seven diets for 4 wk: NC, AC (800 ppb of aflatoxin) with no clay, AC with one of four levels of a treated Ca bentonite (.25, .5, 1, and 2%), or AC and .5% hydrated sodium calcium aluminosilicate. The addition of treated Ca bentonite to AC improved ADG (P < .05) and ADFI (P < .01) linearly. Gain:feed ratios were not affected by treatments. The inclusion of treated Ca bentonite to the AC diet linearly decreased aspartate aminotransferase (AST) levels and quadratically decreased ALP and GGT levels (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of water supplementation with selenium and vitamin E on growth performance and blood selenium and serum vitamin E concentrations in weanling pigs.

OBJECTIVE: To determine effects of supplementation of drinking water with selenium and vitamin E on blood selenium and serum vitamin E concentrations, growth performance, and water intake of pigs. DESIGN: Prospective controlled study. ANIMALS: 228 weanling pigs. PROCEDURE: In experiments 1 and 2, pigs were given drinking water supplemented with selenium and vitamin E, and blood selenium and serum vitamin E concentrations were measured. In experiment 3, growth performance and water intake were measured in pigs that received supplemented water for 2 or 5 weeks and in control pigs. RESULTS: In experiment 1, blood selenium concentrations were significantly increased after 7 days of supplementation, and serum vitamin E concentrations were significantly increased after 1 and 7 days of supplementation, compared with baseline concentrations. In experiment 2, blood selenium concentrations were not significantly different between treated and control pigs, and serum vitamin E concentrations were significantly increased on day 7. In experiment 3, gain-to-feed ratios were significantly higher for pigs supplemented with selenium and vitamin E for 5 weeks, but other differences were not detected. CLINICAL IMPLICATIONS: Supplementation of drinking water with selenium and vitamin E may improve the selenium and vitamin E status of weanling pigs by increasing selenium and vitamin E intake.