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The effects of dietary crude glycerin on growth performance, carcass characteristics, meat quality indices, and tissue histology in growing pigs were determined in a 138-d feeding trial. Crude glycerin utilized in the trial contained 84.51% glycerin, 11.95% water, 2.91% sodium chloride, and 0.32% methanol. Eight days postweaning, 96 pigs (48 barrows and 48 gilts, average BW of 7.9 [+ or -] 0.4 kg) were allotted to 24 pens (4 pigs/pen), with sex and BW balanced at the start of the experiment. Dietary treatments were 0, 5, and 10% crude glycerin inclusion in corn-soybean meal-based diets and were randomly assigned to pens. Diets were offered ad libitum in meal form and formulated to be equal in ME, sodium, chloride, and Lys, with other AA balanced on an ideal AA basis. Pigs and feeders were weighed every other week to determine ADG, ADFI, and G:F. At the end of the trial, all pigs were scanned using real-time ultrasound and subsequently slaughtered at a commercial abattoir. Blood samples were collected pretransport and at the time of slaughter for plasma metabolite analysis. In addition, kidney, liver, and eye tissues were collected for subsequent examination for lesions characteristic of methanol toxicity. After an overnight chilling of the carcass, loins were removed for meat quality, sensory evaluation, and fatty acid profile analysis. Pig growth, feed intake, and G:F were not affected by dietary treatment. Dietary treatment did not affect 10th-rib backfat, LM area, percent fat free lean, meat quality, or sensory evaluation. Loin ultimate pH was increased (P = 0.06) in pigs fed the 5 and 10% crude glycerin compared with pigs fed no crude glycerin (5.65 and 5.65 versus 5.57, respectively). Fatty acid profile of the LM was slightly changed by diet with the LM from pigs fed 10% crude glycerin having less linoleic acid (P < 0.01) and more eicosapentaenoic acid (P = 0.02) than pigs fed the 0 or 5% crude glycerin diets. Dietary treatment did not affect blood metabolites or frequency of lesions in the examined tissues. This experiment demonstrated that pigs can be fed up to 10% crude glycerin with no effect on pig performance, carcass composition, meat quality, or lesion scores. Key words: biofuel, crude glycerin, fatty acid, growing pig, histology, meat quality

The apparent DE and ME values of crude glycerol for growing pigs were determined in 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility, which used soybean oil as the initial feedstock. Dietary treatments were 0, 5, or 10% glycerol addition to basal diets in Exp. 1; 0, 5, 10, or 20% glycerol addition to basal diets in Exp. 2; and 0 and 10% crude glycerol addition to the basal diets in Exp. 3, 4, and 5. Each diet was fed twice daily to pigs in individual metabolism crates. After a 10-d adjustment period, a 5-d balance trial was conducted. During the collection period, feces and urine were collected separately after each meal and stored at 0[degrees]C until analyses. The GE of each dietary treatment and samples of urine and feces from each pig were determined by isoperibol bomb calorimetry. Digestible energy of the diet was calculated by subtracting fecal energy from the GE in the feed, whereas ME was calculated by subtracting the urinary energy from DE. The DE and ME values of crude glycerol were estimated as the slope of the linear relationship between either DE or ME intake from the experimental diet and feed intake. Among all experiments, the crude glycerol (86.95% glycerol) examined in this study was shown to have a DE of 3,344 [+ or -] 8 kcal/kg and an ME of 3,207 [+ or -] 10 kcal/kg, thereby providing a highly available energy source for growing pigs. Key words: biofuel, crude glycerol, metabolizable energy, pig

Corn kernel composition may affect its nutritive value and, thus, pig growth performance and carcass characteristics. The objective of this study was to determine the influence of the chemical and physical traits of corn kernels from different hybrids on the growth performance and carcass characteristics of pigs. A total of 288 crossbred pigs were grown in a 3-phase program from 21 kg of BW until slaughter at 113 kg of BW with 12 pens (4 pigs/pen) per dietary treatment. Target BW for each phase were 20 to 40 kg (grower 1), 40 to 80 kg (grower 2), and 80 to 120 kg (finisher). In each phase, diets were formulated to be marginally deficient in Lys, TSAA, Ca, Na, and nonphytate P to improve the likelihood of detecting differences in performance due to corn hybrid. Each of 6 corn hybrids represented a wide range of kernel chemical and physical traits and was substituted for corn in a common diet formulation on an equal weight basis to make the 6 dietary treatments. Physical and chemical composition of the kernels were analyzed and correlated with performance measures by multivariate ANOVA. Kernel density was correlated with i.m. fat (IMF) content in LM (r = -0.35, P < 0.05). Stenvert grinding time was correlated (P < 0.05) with ADG during the grower 1 phase (r = 0.26), ADFI during the grower 2 phase (r = 0.27), final BW (r = 0.27), and IMF (r = -0.36). The amylose content of the cornstarch was correlated (P < 0.05) with ADG during the grower 2 phase (r = -0.28) and with BW at the end of the grower 2 phase (r = -0.27). The NDF content of the kernels was correlated (P < 0.05) with ADG during the finisher phase (r = -0.30), final BW (r = -0.33), and number of days to market (r = 0.31). The ADF content of the kernels was correlated (P < 0.05) with ADG during the grower 1 phase (r = -0.26), final BW (r = -0.26), and IMF (r = 0.31). The correlations of performance measure variation with individual kernel hybrid physical and chemical traits were statistically significant yet not large enough to base corn hybrid selection for feeding pigs on any single kernel chemical or physical trait. Key words: carcass quality, corn kernel trait, growth performance, swine

Early-weaned pigs (n = 64) averaging 5.3 [+ or -] 0.3 kg and distributed into two environments (dirty and clean) were used to evaluate effects of conjugated linoleic acid (CLA) on growth performance, immune competence, and empty body composition. A factorial (2 x 4) arrangement within a split-plot design, with four littermate pigs as the experimental unit for the environment, pig within litter as the experimental unit for dietary treatment, and d-0 body weight used as covariate, were used in data analysis. Diets were formulated to contain CLA at 0, 0.67, 1.33, or 2% and to exceed the NRC (1988) nutrient needs of pigs. Animals were given ad libitum access to feed for 7 wk in three phases (I, 1 to 2; II, 3 to 5; and III, 6 to 7 wk). Within phases, diets were isocaloric and isonitrogenous. In Phase I, as dietary CLA concentration increased, ADG and ADFI decreased linearly (P [is less than] 0.05 and P [is less than] 0.02, respectively). In Phase II, upon adaptation to dietary CLA supplementation, ADG increased quadratically (603, 623, 622, and 548 g/d; P [is less than] 0.01), ADFI decreased linearly (873, 840, 867, and 717 g/d; P [is less than] 0.02) and gain:feed ratio tended to increase linearly (691, 742, 715, and 763; P [is less than] 0.07). In Phase III, no differences in growth performance were attributed to either dietary or environmental treatments. The poor health status associated with the dirty environment induced a growth suppression; pigs in the clean room had a greater cumulative ADG (P [is less than] 0.01) and ADFI (P [is less than] 0.01) than pigs in the dirty room. In Phase I, lower plasma urea nitrogen levels observed in pigs found in the dirty room (P [is less than] 0.03) indicated a lower protein intake caused by a lower ADFI. The effects of dietary CLA on peripheral phenotypic profiles of lymphoytes did not appear until d 42. However, as indicated by the growth suppression of pigs in the dirty room, the negative effects of the environmental challenge on pig health and growth had already appeared during phase I. On d 42, CLA induced a linear increase in percentages of [CD8.sup.+] lymphocytes (21.7, 22.3, 28.0, and 32.7%; P [is less than] 0.001). These data suggest that a 42-d dietary CLA supplementation preceding a disease challenge could have prevented disease-associated growth suppression. Also, CLA-mediated amelioration of particular infectious diseases will depend on which [CD8.sup.+] T cell subset (i.e., CD8[Alpha][Alpha]-immu-noregulatory or CD8[Alpha][Beta]-cytotoxic) is most influenced by dietary CLA supplementation. Key Words: [CD8.sup.+] Lymphocytes, Cell-Mediated Immunity, Immunomodulators, Linoleic Acid, Pigs

Low-CP diets result in inferior growth performance in both pigs and broiler chicks even though the dietary AA levels meet established requirements. Essential and non-essential crystalline AA (EAA and NEAA, respectively) have been added in various amounts and combinations to low-CP diets in attempts to overcome the growth retardation, albeit to no avail. An experiment was conducted to investigate whether the molecular form of dietary protein influences growth performance of broiler chicks. A total of 240 day-old broiler chicks was fed a common cornsoy diet (23% CP) for 1 wk, after which the chicks were allotted to one of four treatment diets in a completely randomized design (10 chicks per pen, 6 replications). Chicks had free access to feed and water in floor pens and were fed the isoenergetic treatment diets for 2 wk. Treatment diets consisted of a cornsoy diet (D1, 23% CP) and a similar diet, D2, where some of the intact protein was replaced with crystalline EAA and NEAA on a true ileal-digestible basis. The contents of all EAA and all NEAA in D2 were identical to those in D1, differing only in the molecular form of the dietary protein: All protein in D1 was from intact protein, whereas about half the protein in D2 was from crystalline AA. D3 (17% CP) was similar to D2, but with no crystalline NEAA added. Feed disappearance and BW were measured weekly and feed utilization (G:F) calculated. Data were analyzed using GLM and least-squares treatment means were separated using Fishers protected LSD. All diets resulted in different growth performance responses (P < 0.001) with ADG of 42.4, 36.6, and 29.6 g/d; ADFI of 58.4, 53.6, and 51.0 g/d; and G:F of 0.73, 0.68, and 0.58 for D1, D2, and D3, respectively. Differences in feed utilization between chicks fed D1 and D2 indicated that the molecular form of the dietary protein (i.e., intact protein vs free AA) influenced the utilization of the diets. Omission of crystalline NEAA affected growth performance, indicating that nitrogen may be limiting in low-CP diets or that some NEAA may be conditionally essential. Key Words: Low crude protein, Growth performance, Intact protein

Low-CP diets result in inferior growth performance and(or) carcass quality in both pigs and broiler chicks even though the dietary AA levels meet established requirements. Glutamine (Gln) and asparagine (Asn), which have been shown to be conditionally essential and to improve feed utilization in weanling pigs, are inherently low in low-CP diets. An experiment was, therefore, conducted to investigate whether dietary additions of Gln and Asn influence growth performance and nitrogen (N) retention of broiler chicks fed low-CP diets. A total of 240 day-old broiler chicks was fed a common cornsoy diet (23% CP) for 1 wk after which the chicks were allotted to one of four diets in a completely randomized design (10 chicks per pen, 6 replications). Chicks had free access to feed and water in floor pens. All diets were isoenergetic and formulated on a true ileal-digestible AA basis to meet or exceed all NRC requirements. Treatment diets consisted of a cornsoy diet (control, D1, 23.4% CP) and a low-CP diet (D2, 19.2% CP) with 1% triammonium citrate (TAC) included. D3 (19.3% CP) and D4 (18.9% CP) were formulated as D2 with Gln and Asn, respectively, replacing TAC. Feed disappearance and BW were measured weekly and feed utilization (G:F) calculated. After 2 wk on test, chicks were fasted for 24 hours and two chicks per pen were euthanized and the whole-body N content determined. Data were analyzed using GLM and least-squares treatment means were separated using Fishers protected LSD. No differences in growth performance (P > 0.21) or N retention (P > 0.80) were observed among chicks fed the low-CP diets (D2, D3, and D4). Contrasts (low-CP diets vs D1) were, therefore, used to separate the effects of dietary CP level. Chicks fed the low-CP diets had inferior (P < 0.05) ADC (44.6 vs 46.8 g/d), ADFI (65.2 vs 63.2 g/d), G:F (0.68 vs 0.74), and N retention (1.16 vs 1.23 g/d) compared to chicks fed the high-CP diet. Thus, the inferior performance of chicks fed low-CP diets was probably not caused by a deficiency of Gln or Asn. Key Words: Low crude protein, Glutamine, Asparagine