Effects of porcine somatotropin administration on the responses to dietary lysine and a near-ideal blend of amino acids on the amino acid composition of whole-body protein and amino acid accretion rate in growing pigs.

An experiment was conducted to assess the effects of porcine somatotropin (pST) on the responses to a near-ideal blend of AA on the AA composition of empty, whole-empty body (WEB) protein and WEB essential AA accretion rate in pigs from 22 to 60 kg BW. Forty Hampshire × Yorkshire gilts were individually penned and assigned to a 4 × 2 factorial arrangement of treatments consisting of four diets with and without pST injection. A fortified corn-soybean meal basal diet was formulated to contain 1.50% total Lys with Thr, Met, and Trp added to obtain a near-ideal blend of these AA relative to Lys. In three additional diets, Lys was reduced to 1.25%, 1.00%, and 0.75% by diluting the basal diet with cornstarch, cellulose, and sand such that the diets also contained the same ratios of AA. Pigs that received pST were administered a daily i.m. injection of 2 mg of pST. At 60 kg BW, the WEB (carcass, head, viscera, blood, nails, and hair) was ground and analyzed for proximate and AA composition. Administration of pST increased (P < 0.001) accretion rates of WEB protein and essential AA. Increasing dietary essential AA increased (quadratic, P < 0.03) accretion rate of WEB protein, His, Leu, Trp, and Val in pST-treated pigs, but not in untreated pigs. Lysine composition in the accreted WEB protein was not affected (P > 0.05) by dietary Lys. The efficiency of Lys utilization for WEB Lys accretion was linearly affected (P < 0.01) by dietary Lys. These results indicated that the dietary Lys needed to achieve maximum WEB Lys accretion is markedly increased by pST administration.

This study evaluated the effects of two factors, porcine somatotropin and graded levels of amino acids, on the total accumulation and the accretion rate of amino acids across a broad range of protein deposition rates in growing pigs. Treatments included 1) with or without a daily injection of porcine somatotropin and 2) graded levels of total dietary lysine from 0.75% to 1.50%. As expected, both the administration of porcine somatotropin and increased dietary lysine increased both the amount and the rate of amino acid accretion. However, the amount and rate of amino acid accretion from increased dietary amino acids were markedly greater in pigs treated with porcine somatotropin. Thus, the extent to which the genetic potential for protein deposition is achieved depends on both the anabolic capacity of the pig and the amino acid concentration of the diet provided.

Comparative performance of broilers fed diets containing DAS-44406-6 and non-transgenic soybean meal.

Broiler chickens are fast growing monogastric animals considered a sensitive test species to evaluate the safety and nutritional equivalence between transgenic and non-transgenic grains as part of the human safety evaluation process. DAS-44406-6 soybean expresses three herbicide-tolerant proteins: the aryloxyalkanoate dioxygenase-12 (AAD-12) enzyme which provides tolerance to 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides, the double-mutant 5-enolpyruvylshikimate-3-phosphate synthase (2mEPSPS) enzyme encoded by a modified version of the epsps gene from maize (Zea mays), which provides tolerance to glyphosate herbicides, and the phosphinothricin acetyltransferase (PAT) enzyme from Streptomyces viridochromogenes, which provides tolerance to glufosinate herbicides. A 42-day broiler study was conducted with diets containing toasted DAS-44406-6 soybean meal to evaluate nutritional wholesomeness and safety compared with non-transgenic, near-isoline soybean and conventional comparators. The study used a randomized complete block design with five dietary treatments assigned randomly within six blocks of 12 pens per treatment, with 10 birds per pen. Broiler performance and carcass parameters were measured over a 6-week period of exposure to diets containing different sources of toasted soybean meal and hulls. Among the 13 endpoints measured, only thigh weight was numerically different between birds fed DAS-44406-6 soybean meal and those fed isoline soybean meal. However, no significant differences to thigh weight were observed between birds fed DAS-44406-6 soybean and any of the non-transgenic reference varieties. Results indicate that DAS-44406-6 soybeans are nutritionally equivalent to conventional varieties.

Performance of broiler chickens fed diets containing DAS-68416-4 soybean meal.

Broiler chickens are a fast growing monogastric animal commonly used to evaluate the equivalence between transgenic and non-transgenic grains as part of the human safety assessment process. While commonly viewed like other livestock feeding trials, such studies are performed with transgenic crops with input traits (that are not designed to improve nutrition) to aid regulatory authorities in evaluating safety. Studies of this type are actually more similar to toxicology studies in purpose, with sensitive endpoints like growth used to detect metabolic perturbations. DAS-68416-4 soybean expresses the aryloxyalkanoate dioxygenase-12 (AAD-12) enzyme which inactivates 2,4-diclorophenoxyacetic acid (2,4-D) and provides DAS-68416-4 soybeans tolerance to this herbicide. DAS-68416-4 also expresses the phosphinothricin acetyltransferase (PAT) enzyme from Streptomyces viridochromogenes which confers tolerance to glufosinate-ammonium herbicides. A 6-week broiler study was conducted with diets containing toasted DAS-68416-4 soybean meal (40, 36, and 32% in starter, grower and finisher diets, respectively) to evaluate nutritional wholesomeness and safety compared with conventional comparators. Toasting soybean meal is required to inactivate endogenous antinutrients making soybean suitable for consumption by monogastric animals like broiler chickens. Toasting was found to denature both the AAD-12 and PAT proteins rendering them non-detectable by enzyme linked immunosorbent assays. Broiler growth and performance parameters were measured over a 6-week period of exposure to diets containing different sources of toasted soybean meal, and results indicate that DAS-68416-4 soybean is nutritionally equivalent to non-transgenic soybean.

Performance of broiler chickens fed event DAS-40278-9 maize containing the aryloxyalkanoate dioxygenase-1 protein.

Event DAS-40278-9 maize grain (containing the aryloxyalkanoate dioxygenase-1 protein), a non-transgenic near-isogenic maize grain, or one of three commercial maize grains were included in the diets of broiler chickens for six weeks. Growth, feed conversion, and carcass measurements indicated no significant difference between the groups fed the diets containing the DAS-40278-9 maize grain and those fed diets containing the matched control grain. The absence of adverse effects in this study supports the dietary safety of the AAD-1 protein expressed in event DAS-40278-9 maize.

Dietary supplementation of boron differentially alters expression of borate transporter (NaBCl) mRNA by jejunum and kidney of growing pigs.

Inorganic boron (B), in the form of various borates, is readily absorbed across gastrointestinal epithelia. Although there is no stated B requirement, dietary B supplementation is thought to positively affect animal growth and metabolism, including promotion of bone strength and cell proliferation. Because of effective homeostatic control of plasma B levels, primarly by renal excretion, B toxicity in animals and humans is rare. The mechanisms responsible for improved animal performance and borate homeostasis are incompletely understood. Although a Na+-coupled borate transporter (NaBC1) has been identified, the effect of dietary B supplementation on expression of NaBCl has not been evaluated. An experiment was conducted with growing pigs to determine if NaBC1 mRNA was expressed by small intestinal epithelia and kidney of growing barrows and whether dietary B (as borate) supplementation would affect expression of NaBC1 mRNA. A concomitant objective was to test the hypothesis that B supplementation of a phosphorus (P)-deficient diet would improve calcium, phosphorus, or nitrogen retention. Twenty-four crossbred growing barrows (body weight=74.0±9.8 kg) were selected and used in a randomized complete block design experiment with a total of eight blocks and three B supplementation treatments (n=8/treatment). A typical corn-soybean meal basal diet (calculated to contain 41 mg intrinsic B/kg) was formulated to meet or exceed nutrient requirements, except for P, and fed to all pigs for 12 days. The basal diet plus 0, 50, or 100 mg/kg of B (prilled sodium borate pentahydrate, Na2B4O7·5H2O) was then fed for 18 more days. Feces and urine were collected during days 6 to 16 of the B supplementation, and pigs were killed for collection of jejunal and ileal epithelia and kidney tissue. Real-time reverse transcription-PCR analysis revealed that NaBC1 mRNA was expressed by these tissues, a novel finding for jejunal and ileal epithelia. Boron supplementation increased jejunal, but decreased, renal NaBC1 mRNA expression, relative to the 0 mg/kg treatment. The finding that NaBC1 mRNA is regulatable by dietary B is novel. That B supplementation evoked opposite effects on jejunal and kidney NaBC1 mRNA expression indicates that transcriptional regulation of NaBC1 expression may constitute a part of the homeostatic control of B metabolism. In contrast to its effect on NaBC1 mRNA expression, B supplementation did not affect total tract digestibility or retention of phosphorus, calcium, or nitrogen.

Phosphorus utilization in growing pigs fed a phosphorus deficient diet supplemented with a rice bran product and amended with phytase / Utilización de fosforo en cerdos de ceba alimentados con una dieta baja en fosforo, suplementada con salvado de arroz y fitasa / Utilização do fósforo em suínos alimentados com uma dieta baixa em fósforo, suplementada com farelo de arroz e fitase

Rice bran is not only a source of energy for pigs, it also contains significant amounts of phosphorus (P). However, about 75% of this P is not digested by the pig, unless phytase is added to the diet. Once excreted, P may end up contaminating water bodies and thus causing eutrophication. The objectives of this study were to determine the digestibility of P and other nutrients in a diet supplemented with increasing levels of rice bran (0, 7.5, 15, and 30%), and to evaluate the effects of phytase inclusion on the nutrient digestibility of rice bran. Pigs (n= 24, 87.5 ± 2.51kg) were confined in individual metabolic crates to determine total tract apparent digestibility and retention of nutrients. The digestibility coefficients found for dry matter, energy, fat, N, and P in the rice bran product used were: 72, 79, 84, 74, and 15%, respectively. Phytase supplementation increased P digestibility (p<0.01) but it did not increase N digestibility (p>0.1); the increase in fecal P excretion that occurred when rice bran was added to the diet was reduced by 26% with phytase supplementation.

El salvado de arroz no sólo es una interesante fuente de energía para cerdos, sino que contiene bastante fósforo (P). Sin embargo, cerca del 75% de ese P no es utilizable por los cerdos, a menos que se adicione alguna fitasa a la dieta de estos animales. Al no utilizarse, dicho P es excretado, pudiendo contaminar fuentes de agua y generando eutroficación del recurso hídrico. El objetivo del presente trabajo fue establecer la digestibilidad del P y otros nutrientes en una dieta suplementada con niveles crecientes de salvado de arroz (0, 7.5, 15, y 30%), así como evaluar el efecto de la inclusión de fitasa en la digestibilidad de nutrientes del salvado. Para esto se utilizaron 24 cerdos (87.5 ± 2.51kg), confinados en jaulas metabólicas individuales, a los que se les calculó digestibilidad total aparente y retención de nutrientes por el método de Colección Total. Los coeficientes de digestibilidad encontrados fueron: 72, 79, 84, 74, y 15% para materia seca, energía, grasa, N y P, respectivamente. La suplementación con fitasa incrementó la digestibilidad del P (p<0.01), pero no incrementó la digestibilidad del N (p>0.1). El incremento observado en la excreción fecal de P al adicionar salvado de arroz a la dieta fue disminuido en 26% con la adición de fitasa.

O farelo de arroz não é apenas uma fonte de energia interessante para os suínos, ele contém suficiente fósforo (P). No entanto, perto do 75% de P não é usado pelos suínos, a menos que adicione-se alguma fitase na dieta desses animais. Quando não for utilizado, o P é excretado e podem contaminar fontes de água e eutrofização dos recursos hídricos. O objectivo deste estudo foi determinar a digestibilidade do P e outros nutrientes de uma dieta suplementada com níveis crescentes de farelo de arroz (0, 7.5, 15 e 30%), e para avaliar o efeito da fitase sobre a digestibilidade de nutrientes de farelo. Para isso, 24 animais (87.5 ± 2.51 kg), foram confinados em gaiolas metabólicas individuais. Foi calculada a digestibilidade total e retenção de nutrientes pelo método de colheita total. Os coeficientes de digestibilidade encontrados foram: 72, 79, 84, 74 e 15% de matéria seca, energia, gordura, N e P, respectivamente. A suplementação de fitase aumentou o P digestível (p<0.01), porém, aumentou a digestibilidade do N (p>0.1). O aumento observado na excreção fecal de P pela adição de farelo de arroz à dieta foi reduzida em 26% com a adição de fitase.

The effects of dietary chromium(III) picolinate on growth performance, vital signs, and blood measurements of pigs during immune stress.

This experiment used 24 pigs (26.0 kg) to investigate the effects of dietary chromium (Cr) on pigs challenged with lipopolysaccharide (LPS). Following 35 days of diet exposure, the immune stress treatments were: (1) phosphate-buffered saline (PBS) injection and no Cr, (2) LPS injection and no Cr, (3) LPS injection and Cr 1,000 ppb, and (4) LPS injection and Cr 2,000 ppb. At 0 h, PBS or LPS was injected intraperitoneally in each pig. During the first 12 h post-injection, pigs challenged with LPS lost 951 g, while the PBS group gained 170 g (p < 0.001). Compared with the PBS group, LPS-challenged pigs consumed less feed (p < 0.01) during the first 24 h. The LPS group had higher rectal temperature at 2 and 4 h and higher respiratory rate at 1.3 and 8.5 h than the PBS group (p < 0.05). Plasma collected at 3 h had higher cortisol (p < 0.001) and lower glucose (p < 0.05) concentrations in the LPS group than the PBS group. However, supplemental Cr did not affect the response variables. Overall, the LPS challenge affects growth performance, vital signs, and plasma variables, but dietary Cr is unable to moderate stress-related effects associated with an LPS challenge.

Effects of dietary chromium (III) picolinate on growth performance, respiratory rate, plasma variables, and carcass traits of pigs fed high-fat diets.

We investigated the effects of supplemental chromium (Cr) as Cr (III) picolinate on pigs fed high-fat diets (HFD) in a 56-day experiment. Thirty-two crossbred pigs (9.6 kg) were allotted to four treatments with four blocks and two pigs/pen. Treatments included: (1) low-fat diet (fat < 3.5%; LFD) with no Cr, (2) HFD (fat > 30%) with no Cr, (3) HFD with 1,000 ppb Cr, and (4) HFD with 2,000 ppb Cr. Pigs fed HFD gained weight faster, consumed less, and had lower feed:gain (p < 0.05). Pigs fed HFD had higher respiration rates than pigs fed LFD on d 41 (p < 0.05). Plasma insulin on d 14 linearly decreased with Cr (p = 0.05). Plasma cholesterol concentrations were higher in the pigs fed HFD than those fed LFD, but were largely unaffected by supplemental Cr. Consumption of HFD resulted in greater carcass weight, perirenal fat, and backfat measures (p < 0.01) compared with the LFD group. Cr resulted in linear reductions of hot carcass weight (p = 0.08) and average backfat (p < 0.05). The effects of Cr on carcass fat measures were more pronounced in castrated males than in females. These results indicate that Cr attenuates some effects of a HFD, mainly body fat accretion of pigs, and especially in castrated pigs.

Why and how antibiotics are used in swine production.

In summary, published research data clearly show that the use of antibiotics during all phases of growth benefits the rate and efficiency of body weight gain, reduces mortality and morbidity, reduces subclinical disease, and improves health in pigs. Also, antibiotics at breeding and during lactation benefits reproductive and lactational performance in sows. The economic benefits are several-fold greater than the cost of the antibiotic when a cost-effective antibiotic is used for this purpose. Monitoring and surveillance of microbial resistance in animals and humans has continued, with no animal-to-human infection path being clearly delineated. Although the incidence of antibiotic resistance in the human population remains high, there is no clear evidence that the levels or patterns have changed. The high levels of antimicrobial resistance in humans likely result from antibiotics prescribed directly to humans, because well over half of the antibiotics produced in the United States is used in human medicine. Whether antibiotic usage in swine, poultry, and other food-producing animals contributes to antibiotic resistance in the human population will continue to be debated. Even though antibiotics have been fed for nearly 50 years to literally billions of animals, there is still no convincing evidence of unfavorable health effects in humans that can be directly linked to the feeding of subtherapeutic levels of antibiotics to swine or other animals. Hopefully, policy decisions in the future regarding the use of antimicrobials in animals will be based on science and sound risk assessment, and not on emotionalism.