The effect of meal intervals and weaning on feed intake of early weaned pigs

Feed intake was investigated in early weaned pigs housed in two environments. In the first experiment, pigs in an unfamiliar environment (removed from the sow and placed in nursery pens) were offered a dry diet either ad libitum or at different meal intervals (2, 4 and 6 h). Regardless of meal interval (ad libitum or hourly intervals), early weaned (21 d) pigs failed to consume sufficient feed for maintenance during the first 3 d postweaning. Pigs provided feed ad libitum consumed more (P less than .001) feed (142 vs 84 g/d) and gained more (P less than .05) weight (57 vs 3 g/d) than meal-fed pigs over the 7-d period. Pigs fed at 2-h intervals consumed more (P less than .001) feed than pigs fed at 4-h or 6-h intervals. Compared with preweaning levels (307 mu eq/liter), plasma free fatty acid (FFA) levels increased approximately fourfold by d 1 postweaning (1,372 mu eq/liter), then decreased through d 7 to levels below preweaning (142 mu eq/liter). The FFA levels were not affected (P greater than .1) by meal interval. In a second experiment, feed intake was investigated in weaned pigs that were allowed to consume food by a familiar method and in a familiar environment (suckling the sow). When allowed to nurse following a 24-h weaning period, weaned pigs consumed (24.3 +/- 2.8 g/suckling) the same amount (P greater than .1) as non-weaned littermates (28.7 +/- 1.8 g/suckling).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of replacing pharmacological levels of dietary zinc oxide with lower dietary levels of various organic zinc sources for weanling pigs

Two 28-d randomized complete block design experiments were conducted to evaluate the effects of concentrations and sources of Zn on growth performance of nursery pigs. Seven stations participated in Exp. 1, which evaluated the efficacy of replacing 2,500 ppm of Zn from ZnO with 125, 250, or 500 ppm of Zn from Zn methionine. A control diet with 125 ppm of supplemental Zn was included at all stations. A total of 615 pigs were used in 26 replicates. Average weaning age was 20.6 d and the average initial BW was 6.3 kg. There were no differences in any growth response among the three supplemental Zn methionine levels fed in Exp. 1. Zinc supplementation from Zn methionine improved ADG compared with the control during all phases (P < 0.05), due primarily to an increase in ADFI. Pigs fed 2,500 ppm of Zn from ZnO gained faster (P < 0.01) than those fed the control diet during all phases, and faster (P < 0.05) than those fed supplemental Zn from Zn methionine for the 28-d experiment. Differences in gain were again due mainly to differences in feed intake. A second experiment compared five sources of supplemental organic Zn (500 ppm of Zn) with 500 and 2,000 ppm supplemental Zn from ZnO and a control (140 ppm total Zn). Six stations used a total of 624 pigs, with an average weaning age of 20.4 d and averaging 6.2 kg BW in 15 replicates. Pigs fed 2,000 ppm of Zn from ZnO gained faster (P < 0.05) than pigs fed the control or any of the 500 ppm of Zn treatments (ZnO or organic Zn). Pigs fed the 2,000 ppm of Zn from ZnO also consumed more feed than those receiving 500 ppm of Zn from ZnO or from any of the organic Zn sources (P < 0.05). Organic sources of Zn did not improve gain, feed intake, or feed efficiency beyond that achieved with the control diet. Supplemental Zn at a concentration of 500 ppm, whether in the form of the oxide or in an organic form, was not as efficacious for improved ADG as 2,000 to 2,500 ppm of Zn from ZnO.     

Use of chemical characteristics to predict the relative bioavailability of supplemental organic manganese sources for broilers

Twelve organic Mn sources and MnSO4 were evaluated by polarographic analysis and via solubility in buffers (pH 5 and 2) and deionized water. Fractions from solubility tests were evaluated by gel filtration chromatography for structural integrity. Organic Mn sources included five Mn methionine complexes (Mn Met A to Mn Met E), two Mn proteinates (Mn Pro A and Mn Pro B), and five Mn amino acids (Mn AA A to Mn AA E). Sources varied considerably in chemical characteristics. Chelation strength (Qf) ranged from weak (1.9 Qf-values) to strong complexes (115.4 Qf-values). No complexed Mn was found in filtrates at pH 2.0 or 5.0. A 42-d bioassay was used to estimate relative bioavailability of Mn sources for chicks fed diets supplemented with 60, 120, or 180 mg Mn/kg. Bone Mn, heart Mn, heart manganese-superoxide dismutase activity (MnSOD), and heart MnSOD mRNA increased (P < 0.001) as dietary Mn increased. Only heart MnSOD mRNA tended (P < 0.10) to differ among dietary Mn sources. For bioassays of Mn, the MnSOD mRNA level in heart was more sensitive than the MnSOD activity in heart or other indices. Relative to MnSO4 (assigned 100%), slope ratios of MnSOD mRNA levels in heart gave bioavailabilities of 99, 132, and 113% for Mn Met E, Mn AA B, and Mn AA C sources with weak, moderate, and strong chelation strength, respectively. The bioavailability of Mn was more closely related to chelation strength as measured by polarography than to chemical traits assessed by solubility or structural integrity.     

Effect of sensory stimuli on huddling behavior of pigs

Two experiments involving pigs at 1, 3, and 8 d of age were conducted to 1) compare huddling between littermates and nonlittermates, 2) study the ability of pigs to distinguish an anesthetized piglet from a piglet-shaped object, and 3) explore the importance of physical contact between pigs on huddling behavior. Experiments were conducted in an enclosed rectangular aluminum test chamber having pressure sensors beneath floor panels to detect test pig location. Test objects were placed on a platform at one end of the chamber and test pig location was monitored during a 45 min trial. Experiment 1 involved a total of 45 pigs (5 pigs/treatment on d 1, 2, and 3). The results indicate that, regardless of age (P > .05), when either a littermate or a nonlittermate occupied the platform, average location of test pigs that "settled" (ceasing to move for 7 min or more) was closer to the platform (P < .01), time spent near the platform was greater (P < .01), and movement about the chamber was less (P < .01) than when the platform was empty. No differences (P > .05) were observed between littermate and nonlittermate stimuli for these variables. During Exp. 2, the platform was covered with wire mesh. A total of 98 pigs were used in the study. Treatments were a cage containing 1) no object (n = 24), 2) a wooden block (n = 25), 3) a pig-shaped latex casting (n = 24), or 4) an anesthetized 8- to 10-d-old pig (n = 25). Pig age and treatment did not affect the percentage of time in each trial that pigs spent within 23.5 cm of the cage or the percentage of pigs settling within 23.5 cm of the cage. These studies show that pigs huddle similarly with littermates and nonlittermates and that physical contact with another piglet but not visual recognition of another piglet affects piglet huddling.     

Utilization of medium-chain triglycerides by neonatal piglets: II. Effects of even- and odd-chain triglyceride consumption over the first 2 days of life on blood metabolites and urinary nitrogen excretion

In two experiments, 144 neonatal pigs were force-fed 12 ml of triglyceride containing fatty acids of even (C8, C10) or odd (C7, C9) medium-chain length (even-MCT, odd-MCT, respectively) or long- (greater than or equal to C16) chain length (LCT). Pigs were individually caged for measurement of urinary N excretion and(or) blood metabolites over 24 h. In Exp. 1, pigs were force-fed immediately after birth and were not allowed to suckle. Supplementation with triglyceride decreased 24-h N excretion compared with control animals given 12 ml of water, suggesting decreased breakdown of body protein and improved energy status. Blood glucose increased over 24 h in all pigs (P less than .05), but more in pigs given MCT (1.38 mM) than in those given LCT (.61 mM) or in controls (.85 mM) and more in animals given even-MCT (1.87 mM) than in those given odd-MCT (1.14 mM). In Exp. 2, pigs were allowed to suckle and were force-fed at 6, 18 or 48 h of age. An apparent improvement in utilization of even-MCT was observed between 6 and 18 h, as evidenced by a twofold vs a sixfold increase in 3-OH-butyrate (BHBA) concentration 1 h after dosing and a twofold vs 12-fold increase in plasma fatty acid concentration. This was not seen in pigs given odd-MCT. The BHBA response with odd-MCT was approximately half that observed with even-MCT in pigs 18 and 48 h old, but not in pigs 6 h old. No change in BHBA concentration (P greater than .1) was observed in pigs after force-feeding LCT at either 6, 18 or 48 h of age. Collectively, these data suggest that MCT may be better utilized than LCT and that there may be a differences in the utilization of even-MCT vs odd-MCT, depending on the age of the neonate. This could be related to chain length effects on digestion and absorption because plasma decanoate concentration changed very little, even though it composed 25% of the even-MCT supplement.     

Effect of dry, high-moisture and reconstituted normal and high-lysine corn diets and particle size on energy and nitrogen metabolism in growing swine

Two metabolism studies were conducted with 24 (Exp. 1) and 36 (Exp. 2) crossbred barrows (initial weight 35 kg) to determine the effect of corn type--normal corn (NC) and high-lysine corn (HLC)--and storage method--dry (D), high-moisture (HM) and reconstituted (RC)--on energy and N digestibility. Diets fed in Exp. 1 were: 1, NC-soybean meal formulated at .78% lysine (dry matter basis); 2, HLC-soybean meal containing the same amount of corn as diet 1 (.87% lysine); 3, HLC-soybean meal with the same lysine level as diet 1. In Exp. 1, dry matter, energy and N digestibilities were not different between corn types or lysine levels (P greater than .16). These results indicate that energy and N digestibility of HLC in typical diets for growing swine are similar to those for NC diets when both are balanced on a lysine basis. Also, replacing NC with HLC on an equal-weight basis did not affect energy and N digestibility. In Exp. 2 six diets balanced on an isonitrogenous and dry-matter basis were tested. Normal corn and HLC diets, which had been stored by three different methods (D, HM and RC) were arranged in a 2 X 3 factorial plan. There were no differences between corn types in dry matter, energy and N digestibilities. The HM and RC treatments had larger particle sizes than the dry corn diets. For diets balanced on an isonitrogenous basis, dry corn storage improved energy digestibility (P less than .10). Reconstitution appeared to improve energy balance and N digestibility of HLC, while HM storage improved energy balance and N digestibility of NC.