Effects of graded levels of dietary copper on copper and iron concentrations in swine tissues.

In a dose-response study, 120 weanling, crossbred pigs were used to determine the effect of 7.5, 15, 30, 60, 120 and 240 ppm total dietary Cu on animal performance and Cu and Fe stores in selected tissues. Pigs were killed at 56 or 91 kg average body weight. Average daily gain was not affected by dietary treatment. Dietary Cu concentrations of 7.5, 15, 30 and 60 ppm had no appreciable effect on Cu and Fe concentrations in liver and kidney of pigs slaughtered at 91 kg. However, 120 and 240 ppm dietary Cu increased (P less than or equal to .01) liver Cu 4.5- and 16-fold and decreased (P less than or equal to .05) liver Fe by 50 and 60%, respectively, compared with the other dietary treatments. A fit of liver Cu and Fe data to linear plateau models resulted in an inflection point of approximately 60 ppm dietary Cu. Kidney Cu was also increased (P less than or equal to .05) by 120 and 240 ppm dietary Cu, but the magnitude of the change was smaller than that of liver Cu. Muscle Cu and Fe were not significantly affected by dietary Cu.

Compensatory growth and nitrogen balance in grower-finisher pigs.

Sixteen castrated male pigs (averaging 21.2 +/- 4.9 kg) were used in two trials to investigate the effect of dietary amino acid content during the grower phase on growth performance and N balance. In each trial, pigs were assigned randomly to corn-soybean meal grower diets formulated to contain 5.0 or 11.0 g lysine/kg (as-fed basis). Common Finisher 1 and 2 diets were offered when pigs reached 51.2 +/- 3.3 and 79.5 +/- 3.4 kg, respectively. Pigs were placed in metabolism crates for a 9-d period during each of the grower, Finisher 1, and Finisher 2 phases when they weighed 43.3 +/- 3.9, 70.4 +/- 4.9, and 90.5 +/- 3.8 kg, respectively, to determine N balance. Blood samples were taken from each pig periodically after an overnight fast. Pigs were allowed ad libitum access to feed and water, except during the three adaptation/collection periods. There were no diet x trial interactions; thus, the data were combined. Pigs fed the low-amino acid grower diet grew more slowly and less efficiently (P < 0.001) during the grower phase and had more ultrasound backfat (P = 0.010) at the end of the grower phase than those fed the high-amino acid grower diet. During the Finisher 1 phase, however, pigs fed the low-amino acid diet grew more efficiently (P = 0.012) than those fed the high-amino acid diet, and the grower diet had no effect on overall weight gain, carcass traits, lean accretion, or meat quality scores. Although pigs fed the low-amino acid diet had less serum urea N (P < 0.001) and more glucose (P = 0.009) at 43.3 kg, there seemed to be no clear, long-term effect of the grower diet on serum metabolites. During the grower phase, pigs fed the high-amino acid diet consumed more N (P < 0.001), had higher apparent N digestibility (P = 0.041), N utilization (P = 0.027), and N retention (P < 0.001), and excreted more fecal (P = 0.034) and urinary (P < 0.001) N than those fed the low-amino acid diet. Pigs fed the low-amino acid grower diet, however, had a higher N utilization (P = 0.024) during the Finisher 1 phase, and excreted less urinary N during both the Finisher 1 (P = 0.029) and 2 (P = 0.027) phases than those fed the high-amino acid grower diet. These results indicate that pigs subjected to early dietary amino acid restrictions compensated completely and decreased N excretion during both the restriction and realimentation phases. Compensatory growth can, therefore, have a positive effect not only on the overall efficiency of pig production but also on environment.

Improving pork quality by feeding supranutritional concentrations of vitamin D3.

Duroc-cross pigs (n = 25) were assigned to one of three experimental finishing diets containing 0 (control), 40,000 (40), or 80,000 (80) IU of supplemental vitamin D3/kg of feed (as-fed basis)to test the effects of vitamin D3 on pork quality traits. Experimental diets were fed for 44 or 51 d before slaughter, and days on feed were blocked in the experimental design. A trend existed for pigs receiving the highest concentration of vitamin D3 supplementation to have a lower (P = 0.08) ADG (0.77 kg/d) compared with pigs fed either the 40-diet (0.88 kg/d) or control (0.92 kg/d). Diet did not (P > 0.10) affect backfat thickness measured along the midline, 10th-rib fat depth, longissimus muscle area, muscle score, or hot carcass weights. Longissimus pH, measured at 0.5, 1, 2, 3, 4, and 24 h postmortem, was higher (P < 0.05) for pigs on the 80-diet than those fed the control diet. Longissimus muscle color, measured at 24 h postmortem, from pigs fed either the 40- or 80-diet were darker (lower L* values; P < 0.05) than those fed the control diet. Objective longissimus color scores were higher (P < 0.01), and firmness/wetness scores lower (P < 0.05), for pigs on the 80-diet as compared to those on the 40-diet or control diet. The diet had no (P > 0.10) effect on Warner-Bratzler shear force values; percentage of cook loss; or trained sensory panel evaluations for tenderness, juiciness, and flavor. Feeding the 80-diet increased (P < 0.05) plasma vitamin D3 and calcium after 2, 4, and 6 wk on feed compared with the control diet. Vitamin D3 and 25-hydroxy vitamin D3 concentrations in the longissimus muscle increased (P = 0.001) with increasing vitamin D3 levels in the diet; however, muscle calcium concentrations and fiber type were not (P > 0.30) affected by diet. These results indicate that feeding supranutritional levels of vitamin D3 for at least 44 d improves pork color and increases pH, but may retard growth if fed at 80,000 IU/kg of feed.

Growth performance, dry matter and nitrogen digestibilities, serum profile, and carcass and meat quality of pigs with distinct genotypes.

We investigated the effect of distinct genotypes on growth performance, DM and N digestibilities, serum metabolite and hormonal profiles, and carcass and meat quality of pigs. Eight control-line and eight select-line pigs with an equal number of gilts and castrated males per genotype were chosen from the group of pigs subjected to selection for lean growth efficiency. Pigs were housed individually and allowed ad libitum access to common grower, finisher 1, and finisher 2 diets when they reached approximately 20, 50, and 80 kg, respectively, and water throughout the study. Although genotype had no effect on growth performance during the finisher 2 phase and overall, select-line pigs grew faster and more efficiently (P < 0.05) during the grower and finisher 1 phases than did control-line pigs. Dry matter and N digestibilities during the grower phase were lower (P < 0.05) in select-line pigs compared with control-line pigs. Select-line pigs had less ultrasound backfat (P < 0.05) at the end of the grower and finisher 2 phases. Serum urea N (P < 0.05) and leptin concentrations were lower in select-line pigs than in control-line pigs, but the effect of genotype on serum glucose, triglyceride, or insulin concentration was rather inconsistent. Select-line pigs had heavier heart (P < 0.05), liver (P = 0.08), and kidneys (P < 0.01), implying a higher metabolic activity. Less 10th-rib carcass backfat (P < 0.01) and a trend for larger carcass longissimus muscle area (P = 0.10) were reflected in the greater (P < 0.01) rate and efficiency of lean accretion in select-line pigs. Select-line pigs had lower subjective meat color (P < 0.01), marbling (P < 0.05), and firmness (P < 0.01) scores. Final serum leptin concentration was correlated positively with carcass backfat thickness (r = 0.73; P < 0.01) and negatively with overall feed intake (r = -0.77; P < 0.01). These results indicate that pigs with distinct genotypes exhibited differences in the growth rate, metabolite and hormonal profiles, and body composition. Further research is necessary to determine whether pigs with distinct genotypes respond differently to dietary manipulations, which would have an effect on developing optimal feeding strategies for efficient and sustainable pig production.

Effects of dietary 1,3-butylene glycol on adipose tissue metabolism from lean and obese swine.

One,three-butylene glycol (BG) was isocalorically substituted for glucose and fed ad libitum to lean (XB) and obese (HL) swine at 0, 10, and 20% of the total dietary ME from 25 kg body weight until slaughter at 90 kg. BG depressed rate and efficiency of gain in both groups. Plasma beta-hydroxybutyrate concentration was increased by the ketogenic energy substitution. Plasma glucose and free fatty acids were not influenced by diet composition. Adipose tissue utilization of glucose for lipogenesis was depressed by BG in both XB and HL animals after 4 wk of treatment. Insulin added in vitro increased glucose utilization by approximately 20% in adipose tissue from both breed groups; however, the BG induced depression of glucose utilization for fatty acid synthesis was still evident. Insulin-stimulated glucose utilization was greater in XB then in L swine. After 12 wk of dietary treatment, animals given BG had significantly increased plasma insulin concentration and decreased plasma urea concentrations. Although the absolute rates of lipogenesis had decreased after 12 wk of treatment, similar diet-related results were obtained. Insulin did not stimulate glucose utilization by adipose tissue from animals of either breed group at this latter sampling. Fatty acid esterification was slightly depressed by BG at the 4 wk sampling, but after 12 wk of treatment, only a significantly breed group effect was evident. Subcutaneous fat thickness, loineye area and carcass percentage lean cuts were not influenced by diet composition. This experiment demonstrated that ketogenic energy and substitution in the diet does depress the rate of de novo lipogenesis from glucose as measured by in vitro incubation of swine adipose tissue. Supplementation of the incubation media with massive quantities of insulin did not reverse the dietary treatment effects, and animals of both lean and obese phenotypes responded similarly to the dietary treatment. The absence of dietary treatment effects on indices of body fat content suggest that ketone bodies may be substituted for glucose as a lipogenic substrate in swine.

Degree of amino acid restrictions during the grower phase and compensatory growth in pigs selected for lean growth efficiency.

A total of 32 select line (SL) and 32 control line (CL) Duroc pigs were used in two trials to determine the effect of dietary amino acid contents during the grower (G) phase and selection for lean growth efficiency on growth performance, carcass traits, and meat quality. In each trial, pigs weighing 20 kg were assigned to 16 pens with two gilts or two castrated males per pen, and pens were randomly assigned within the genetic line to corn-soybean meal G diets formulated to contain 5.0, 7.0, 9.0, or 11.0 g lysine/kg. After 50 kg, all pigs were fed common finisher 1 (F1) and finisher 2 (F2) diets. Pigs were allowed ad libitum access to feed and water. After the initial statistical analyses, the data sets from the two trials were combined. During the G phase, pigs consumed less feed [linear (Ln), P < 0.001] and more lysine (Ln, P < 0.001), grew faster (Ln, P < 0.05) but utilized feed more and lysine less efficiently (Ln, P < 0.001) for weight gain as the amino acid content of G diets increased. Increasing dietary amino acids resulted in less ultrasound backfat (Ln, P < 0.001) and more serum urea nitrogen [Ln, P < 0.001; quadratic (Qd), P < 0.01] at the end of the G phase. Pigs grew more slowly during the F1 (Ln, P < 0.01 and Qd, P = 0.05) and F2 (Ln, P = 0.07) phases and utilized feed and lysine less efficiently (Ln, P < 0.05) for weight gain during the F1 phase as the amino acid content of G diets increased. The grower diet had no effect on overall weight gain and feed efficiency, carcass traits, or meat quality scores. The efficiency of lysine utilization for overall weight gain (Ln, P < 0.001) and lean accretion (Ln, P < 0.05) improved as the amino acid content of G diets decreased. The SL pigs grew faster (P < 0.05) and had less (P < 0.001) ultrasound backfat throughout the study compared with the CL pigs. The SL pigs had less 10th rib backfat (P < 0.001) and tended to have larger longissimus muscle area (P = 0.09) than the CL pigs, which were reflected in greater rate (P < 0.001) and efficiency (P < 0.05) of lean accretion. Marbling (P < 0.05) and meat color (P = 0.07) scores were lower in the SL pigs. No grower diet x genotype interactions were observed in response criteria of interest. The results indicate that pigs subjected to dietary amino acid restrictions during the G phase (as low as 5.0 g lysine/kg) compensated completely in terms of growth rate and body composition regardless of the genotype. Compensatory growth can have a positive impact not only on the overall efficiency of pig production but also on the environment by reducing excretion of unused nutrients.

Sulfamethazine blood/tissue correlation study in swine.

Seventy market-weight hogs (90 to 113 kg) were used in a feeding study to determine the correlation of serum sulfamethazine concentrations with sulfamethazine concentrations in liver and muscle at time of slaughter. Test groups were fed medicated feeds prepared from commercial medicated premixes containing 110 g of sulfamethazine/metric ton for 30 days. Fifteen days before hogs were slaughtered, test groups were given maintenance feeds containing 1.1 to 13.9 g of sulfamethazine/metric ton and were fed these diets until slaughtered. Comparison of data from positive- and negative-control groups indicated that total withdrawal of sulfamethazine in the feed was not necessary for the liver to contain less than the allowed tolerance of 0.1 mg of sulfamethazine/kg of liver at slaughter. Feed concentrations of up to 2 g of sulfamethazine/metric ton could be tolerated in withdrawal feeds before liver sulfamethazine values exceeded 0.1 mg/kg of liver. Serum/tissue sulfamethazine ratios were erratic in hogs given 1.1 to 2.7 g of sulfamethazine/metric ton, but became less variable in hogs given greater than 5.7 g/metric ton. Feed concentrations greater than 8 g of sulfamethazine/metric ton produced values greater than 0.1 mg/kg of muscle and values of about 0.4 mg/kg of liver. When serum sulfamethazine concentrations alone were used as a predictor for tissue sulfamethazine values, 100% of the liver values exceeded 0.10 mg/kg of liver when sulfamethazine in serum was greater than 0.45 mg/L. However, 57.4% of samples having serum concentrations between 0.10 and 0.45 mg/L had associated sulfamethazine values greater than 0.1 mg/kg of liver. All hogs having serum sulfamethazine concentrations less than 0.1 mg/L had sulfamethazine concentrations less than 0.1 mg/kg of liver.

Dietary restrictions during adolescence and subsequent reproductive performance of turkey breeder males.

A study was conducted to investigate the effect of early dietary restriction of protein and/or energy on the subsequent reproductive ability of the tom. One hundred 8-week old Large White turkey toms (April hatch) were placed at random into four floor pens of 25 each and fed the following diets: group 1, 20.6% protein with 2,4 Mcal. M.E./kg. diet 8-12 weeks, 15.3% protein with 2.68 Mcal. 12-16 weeks, 10.4% protein with 2.85 Mcal. 16-24 weeks; group 2, 20.3% protein with 2.9 Mcal. 8-12 weeks, 14.8% protein with 2.98 Mcal. 12-16 weeks, 9.8% protein with 3.27 Mcal. 16-24 weeks; group 3, 22% protein with 2.4 Mcal. 8-12 weeks, 18.9% protein with 2.57 Mcal. 12-16 weeks, 16.3% protein with 2.81 Mcal. 16-24 weeks; group 4 (control), 22% protein with 2.91 Mcal. 8-12 weeks, 19% protein with 3.03 Mcal. 12-16 weeks, 15.9% protein with 3.17 Mcal. 16-24 weeks. Beginning with the 25th weeks all toms received a 14.3% protein diet with 2.8 Mcal. The restriction of energy significantly reduced the percentage of males producing semen, and the restriction of energy significantly reduced the percentage of males producing semen, and the restriction of energy and both protein and energy significantly depressed semen volume per male in comparison with the average produced by the control males. Other reproductive traits were not affected by early dietary controls.

Glycogen depletion and repletion in the chick.

Carcass glycogen was degraded by chicks at a faster rate than liver glycogen during the first 72 hr of a 120 hr fast. Degradation of both sources of glycogen proceeded at a slower rate during the final 48 hr. Carcass glycogen was repleted at a greater rate than liver glycogen.

Glycogen metabolism in the turkey embryo and poult.

Fertile eggs from Large White turkey hens were classified according to weight at time of incubation. Glycogen was measured in the 21-day-old embryo and one-day-old poult. Liver glycogen was positively correlated with initial egg weight in the 21-day-old embryo and negatively related to initial egg weight in the one-day-old poult. Glycogen recycling was evident in the one-day-old poult. Maximum accumulation of 14C-glucose as glycogen occurred 60 min post injection. Liver phosphorylase a level was higher in the one-day-old poult than the embryo. Total phosphorylase per gram of liver tissue was not different between the two age groups. Liver phosphorylase b was subject to conversion to phosphorylase a in both age groups. Avian phosphorylase exists in both the active and inactive form.

Effect of dietary energy on hepatic glycogen metabolism in the turkey hen.

An experiment was conducted with turkey hens to investigate the effect of substituting 30% of the carbohydrate calories with corn oil, 1,3-butanediol, or glycerol. Birds fed additional corn oil had the lowest liver glycogen concentration. Corn oil increased phosphorylase, a total phosphorylase, and glycogen synthetase I in comparison to the controls. Also, additional corn oil resulted in the highest specific activity of glucose-6-phosphatase. Dietary glycerol caused the highest concentration of liver glycogen. Glycerol increased glycogen synthetase I, but had little effect upon total activity in comparison to butanediol in the diet. Both butanediol and glycerol gave similar phosphorylase a activity, but butanediol increased total activity. The fat-fed and control-fed hens regulated hepatic glycogen concentration through phosphorylase, while glycerol and butanediol-fed hens regulated glycogen through glycogen synthetase. In vitro activation of glycogen synthetase I was deficient in hens fed additional corn oil, indicating a lack of glycogen synthetase phosphatase activity. The order of activation (glycerol greater than butanediol greater than control greater than corn oil) corresponds to the rank of glycogen concentrations

Studies on the role of lysine and protein in the regulation of lipogenesis by the turkey poult.

Two feeding trials were conducted with Large White turkey poults to determine the role of lysine or protein level on growth and in vitro lipogenesis in turkey poults. Basal 23 and 30% protein diets were formulated with corn and soybean meal. Lysine HCl was added to the 23% protein diet in varying quantities. The soybean-to-corn meal ratio was adjusted in another series of diets to increase the lysine and protein levels. Growth and feed consumption were noted as functions of either lysine or protein levels. In vitro lipogenesis from alanine, lactate, or acetate was determined in the first experiment, whereas in vitro lipogenesis from acetate was determined in the presence of lactate or alanine in the second experiment. Lysine HCl increased (P less than .05) in vitro lipogenesis; however, increasing the lysine level with soybean meal decreased (P less than .05) lipogenesis. A great decrease in lipogenesis occurred when the protein level was increased from 25.3 to 26.8%. Lactate and alanine were used by liver tissue as substrates for lipogenesis and increased (P less than .05) lipogenesis from acetate.

Effect of protein and amino acid status on lipogenesis by turkey poults.

Feeding trials were conducted with large White turkey poults to determine the role of dietary protein, sulfur amino acid (SAA), and lysine levels on growth and in vitro lipogenesis by turkey poults. A basal, 23% protein diet was formulated to contain 75% of the National Research Council (NRC) requirement for both SAA (8.0 g/kg) and lysine (12.9 g/kg). Lysine hydrochloride and L-methionine were added to the basal diet. A 30% protein diet was formulated to contain 100% of the requirement for SAA and lysine and served as the dietary control treatment. Twenty-three percent protein diets supplemented to contain the required levels of SAA (10.5 g/kg) and lysine (17.0 g/kg) supported growth and feed consumption equal to that attached with the control diet. Glutamic-aspartic amino transferase (GAT) and isocitrate dehydrogenase (ICD) activities were decreased (P less than 0.5) by 23% protein compared to 30% protein. Lysine additions to the 100% SAA diets increased GAT activity; however, additional lysine had little effect upon ICD activity. Each increment of lysine, whether fed to conjunction with 75 or 100% SAA, increased malic enzyme (ME) activity. It is suggested from the study that both GAT and ICD reflect the protein nutritional status of the poult and ME its lipogenic capacity. Lysine added to 23% protein diets increased (P less than .05) in vitro lipogenesis; however, this effect could be moderated by increasing the SAA level from 75 to 100% of the requirement. Liver slices preferentially used lactate over alanine as a lipid precursor; however, both lactate and alanine stimulated acetate incorporation into lipid equally. Liver slices did not use glucose for lipid synthesis to the degree that they used alanine, lactate, or acetate.

Effects of dietary fat on feed efficiency, reproductive performance, and in vitro lipogenesis by the turkey hen.

Two 16-week feeding trials were conducted with Large White turkey hens to determine the effect of graded energy levels (as fat-6, 18, 30, and 42% substituted isocalorically for corn meal) on energy efficiency, reproductive performance, lipogenic enzyme activity, and in vitro lipogenesis. A constant calorie: gram-protein ratio (17:1) was maintained for all dietary treatments. Also, other components of the diets were adjusted to maintain constant energy-to-nutrient ratios. Additional fat increased (P less than .05) energy utilization but had no effect on reproductive performance. Additional fat calories decreased (P less than .05) malic enzyme, isocitrate dehydrogenase, and fatty acid synthetase activities; however, fatty acid synthetase activity was the most responsive of the three enzymes to 42% metabolizable energy as fat. Liver lipid content was also decreased (P less than .05) by additional fat calories. In vitro lipogenesis (fatty synthesis from 10 mM (1-14C) sodium acetate) was also decreased (P less than .01) by additional dietary fat.