Supplementing limited methionine diets with rumen-protected methionine, betaine, and choline in early lactation Holstein cows.

Eighty lactating Holstein cows from 21 to 91 d in milk were fed a corn silage-based total mixed ration (TMR) formulated with the Met content limited (42 g/ d) to investigate the impact of supplementing rumen-protected (RP) forms of Met, betaine, and choline on performance and metabolism. One of 4 supplements was blended into the TMR to produce 4 dietary treatments: 1) control, 2) 20 g/d of RP-Met, 3) 45 g/d of RP-betaine, and 4) 40 g/d of RP-choline. Calcium salts of fatty acids were used to protect both RP-betaine and RP-choline supplements. A similar amount of Ca salts of fatty acids was included in both control and RP-Met supplements to provide equal amounts of fat to all treatments. Overall, no differences in intake, milk yield, or milk composition were observed in primiparous cows. Average dry matter intake, body weight, and body condition score were not different among treatments in multiparous cows. Milk yield was higher in multiparous cows fed RP-choline compared with the other treatments. Multiparous cows fed RP-choline had higher milk protein yield than cows fed control or RP-betaine but was not different from cows fed RP-Met. Multiparous cows fed RP-choline had higher milk fat yield than cows fed RP-Met but was not different from cows fed control or RP-betaine. There were no beneficial effects of RP-betaine supplementation to a Met-limited TMR.

Effects of feeding L-carnitine to gilts through day 70 of gestation on litter traits and the expression of insulin-like growth factor system components and L-carnitine concentration in foetal tissues.

We investigated the influence of supplemental L-carnitine on foetal blood metabolites, litter characteristics, L-carnitine concentration in skeletal muscle and insulin-like growth factor (IGF) axis components in foetal hepatic and skeletal muscle tissues at day 40, 55 and 70 of gestating gilts. A total of 59 gilts (body weight = 137.7 kg) received a constant feed allowance of 1.75 kg/day and a top-dress containing either 0 or 50 ppm of L-carnitine starting on the first day of breeding through the allotted gestation length. Foetuses from the gilts fed diets with L-carnitine tended to be heavier (p = 0.06) and the circulating IGF-II tended to be lower (p = 0.09) at day 70, compared with the foetuses from the control gilts. Insulin-like growth factor-I messenger RNA (mRNA) was lower (p = 0.05) in hepatic tissue in the foetuses collected from gilts fed L-carnitine. Free and total carnitine concentration increased (p < 0.05) in the skeletal muscle from the foetuses collected from gilts fed supplemental L-carnitine. This study showed that L-carnitine had beneficial effects on the average foetal weight at day 70 of gestation, associated with changes in the foetal IGF system.

Impact of maternal heat stress in conjunction with dietary zinc supplementation on hatchability, embryonic development, and growth performance in offspring broilers.

The aim of this study was to investigate whether maternal dietary supplementations with different zinc (Zn) sources could reduce the deleterious effect of maternal heat stress on hatchability performance and progeny growth performance. A completely randomized design (n = 6) with 2 maternal environmental temperatures [normal 21 ± 1°C (NT) vs. high 32 ± 1°C (HT)] × 3 maternal dietary supplemental Zn levels [Zn-unsupplemented control diet (CON), the control diet + 110 mg of Zn/kg of diet as either inorganic ZnSO4 (iZn) or organic Zn with a moderate chelation strength (oZn)] was used. HT decreased (P < 0.05) fertility, hatchability, chick hatch weight, and embryonic survival. HT also decreased (P ≤ 0.05) progeny BW, ADG, and ADFI at one to 21, 22 to 28, and 29 to 42 d of age as well as breast muscle ratio and plasma aspartate aminotransferase and creatine kinase activities at 42 d of age. Maternal dietary Zn supplementation with either iZn or oZn increased (P < 0.004) Zn contents in yolk and liver, non-weak chick ratio, as well as progeny BW, ADFI, and survivability at one to 21 d of age. Notably, the addition of oZn increased (P < 0.05) hatchability and progeny thigh meat quality by reducing b* value. The progeny ADG at one to 21 d and 22 to 28 d of age and BW at 28 d of age from maternal NT were not affected (P > 0.46) by maternal dietary Zn supplementation, but the above 3 indices from HT-iZn (P < 0.05) and HT-oZn (P < 0.003) were higher than those from HT-CON. Our results indicate that maternal heat stress impairs hatching performance, embryonic development, and progeny growth performance, inducing metabolic changes, while supplementation of Zn in maternal diets regardless of Zn sources improved hatch chick quality and survivability of offspring and alleviated the negative effect of maternal heat stress on growth performance of offspring during the starter period. In addition, maternal dietary supplementation with the organic Zn improved hatchability and progeny meat quality.

Conjugated linoleic acid evokes de-lipidation through the regulation of genes controlling lipid metabolism in adipose and liver tissue.

Conjugated linoleic acid (CLA) is a unique lipid that elicits dramatic reductions in adiposity in several animal models when included at < or = 1% of the diet. Despite a flurry of investigations, the precise mechanisms by which conjugated linoleic acid elicits its dramatic effects in adipose tissue and liver are still largely unknown. In vivo and in vitro analyses of physiological modifications imparted by conjugated linoleic acid on protein and gene expression suggest that conjugated linoleic acid exerts its de-lipidating effects by modulating energy expenditure, apoptosis, fatty acid oxidation, lipolysis, stromal vascular cell differentiation and lipogenesis. The purpose of this review shall be to examine the recent advances and insights into conjugated linoleic acid's effects on obesity and lipid metabolism, specifically focused on changes in gene expression and physiology of liver and adipose tissue.

Impact of dietary lipids on sow milk composition and balance of essential fatty acids during lactation in prolific sows.

Two studies were designed to determine the effects of supplementing diets with lipid sources of EFA (linoleic and α-linolenic acid) on sow milk composition to estimate the balance of EFA for sows nursing large litters. In Exp. 1, 30 sows, equally balanced by parity (1 and 3 to 5) and nursing 12 pigs, were fed diets supplemented with 6% animal-vegetable blend (A-V), 6% choice white grease (CWG), or a control diet without added lipid. Diets were corn-soybean meal based with 8% corn distiller dried grains with solubles and 6% wheat middlings and contained 3.25 g standardized ileal digestible Lys/Mcal ME. Sows fed lipid-supplemented diets secreted greater amounts of fat (P = 0.082; 499 and 559 g/d for control and lipid-added diets, respectively) than sows fed the control diet. The balance of EFA was computed as apparent ileal digestible intake of EFA minus the outflow of EFA in milk. For sows fed the control diet, the amount of linoleic acid secreted in milk was greater than the amount consumed, throughout lactation. This resulted in a pronounced negative balance of linoleic acid (-22.4, -38.0, and -14.1 g/d for d 3, 10, and 17 of lactation, respectively). In Exp. 2, 50 sows, equally balanced by parity and nursing 12 pigs, were randomly assigned to a 2 × 2 factorial arrangement of diets plus a control diet without added lipids. Factors included linoleic acid (2.1% and 3.3%) and α-linolenic acid (0.15% and 0.45%). The different concentrations of EFA were obtained by adding 4% of different mixtures of canola, corn, and flaxseed oils to diets. The n-6 to n-3 fatty acid ratios in the diets ranged from 5 to 22. Increasing supplemental EFA increased (P < 0.001) milk concentrations of linoleic (16.7% and 20.8%, for 2.1% and 3.3% linoleic acid, respectively) and α-linolenic acid (P < 0.001; 1.1 and 1.9% for 0.15 and 0.45% α-linolenic acid, respectively). Increasing supplemental EFA increased the estimated balance of α-linolenic acid (P < 0.001; -0.2 and 5.3 g/d for 0.15% and 0.45% α-linolenic acid, respectively), but not linoleic acid (P = 0.14; -3.4 and 10.0 g/d for 2.1% and 3.3% linoleic acid, respectively). In conclusion, lipid supplementation to sow lactation diets improved milk fat secretion. The fatty acid composition of milk fat reflected the dietary supplementation of EFA. The net effect of supplemental EFA was to create a positive balance during lactation, which may prove to be beneficial for the development of nursing piglets and the subsequent reproduction of sows.

Development of prediction equations to estimate the apparent digestible energy content of lipids when fed to lactating sows.

Two studies were conducted 1) to determine the effects of free fatty acid (FFA) concentrations and the degree of saturation of lipids (unsaturated to saturated fatty acids ratio [U:S]) on apparent total tract digestibility (ATTD) and DE content of lipids and 2) to derive prediction equations to estimate the DE content of lipids when added to lactating sow diets. In Exp. 1, 85 lactating sows were assigned randomly to a 4 × 5 factorial arrangement of treatments plus a control diet with no added lipid. Factors included 1) FFA concentrations of 0, 18, 36, and 54% and 2) U:S of 2.0, 2.8, 3.5, 4.2, and 4.9. Diets were corn-soybean meal based and lipid was supplemented at 6%. Concentrations of FFA and U:S were obtained by blending 4 lipid sources: choice white grease (CWG; FFA = 0.3% and U:S = 2.0), soybean oil (FFA = 0.1% and U:S = 5.5), CWG acid oil (FFA = 57.8% and U:S = 2.1), and soybean-cottonseed acid oil (FFA = 67.5% and U:S = 3.8). Titanium dioxide was added to diets (0.5%) as a digestibility marker. Treatments started on d 4 of lactation and fecal samples were collected after 6 d of adaptation to diets on a daily basis from d 10 to 13. The ATTD of added lipid and DE content of lipids were negatively affected (linear, < 0.001) with increasing FFA concentrations, but negative effects were less pronounced with increasing U:S (interaction, < 0.05). Coefficients of ATTD for the added lipid and DE content of lipids increased with increasing U:S (quadratic, = 0.001), but these improvements were less pronounced when the FFA concentration was less than 36%. Digestible energy content of added lipid was described by DE (kcal/kg) = [8,381 - (80.6 × FFA) + (0.4 × FFA) + (248.8 × U:S) - (28.1 × U:S) + (12.8 × FFA × U:S)] ( = 0.74). This prediction equation was validated in Exp. 2, in which 24 lactating sows were fed diets supplemented with 6% of either an animal-vegetable blend (A-V; FFA = 14.5% and U:S = 2.3) or CWG (FFA = 3.7% and U:S = 1.5) plus a control diet with no added lipids. Digestible energy content of A-V (8,317 and 8,127 kcal/kg for measured and predicted values, respectively) and CWG (8,452 and 8,468 kcal/kg for measured and predicted values, respectively) were accurately estimated using the proposed equation. The proposed equation involving FFA concentration and U:S resulted in highly accurate estimations of DE content (relative error, +0.2 to -2.3%) of commercial sources of lipids for lactating sows.

Effects of maternal dietary manganese and incubation temperature on hatchability, antioxidant status, and expression of heat shock proteins in chick embryos.

To investigate whether supplementing manganese (Mn) to the maternal diet could reduce the deleterious effect of heat stress on the developing embryo, the hatchability, antioxidant status, and expression of heat shock proteins (HSP) were evaluated in chick embryos under normal and high incubation temperatures. A completely randomized design ( = 6) with 2 maternal dietary Mn treatments (unsupplemented control basal diet versus the basal diet + 120 mg Mn/kg as inorganic Mn) × 2 incubation temperatures (normal, 37.8°C, versus high, 39.0°C) was used. High incubation temperature did not affect ( > 0.19) hatchability and embryo mortality and development but did increase ( < 0.05) activities of heart manganese superoxide dismutase (MnSOD) and liver copper zinc superoxide dismutase and liver MnSOD mRNA and protein levels in embryos. High incubation temperature also decreased ( < 0.003) HSP70 protein level in the heart but had no effects ( > 0.07) in the liver of embryos. Maternal diet with Mn supplementation not only increased ( < 0.05) the hatchability and Mn content ( < 0.001) in the yolk and embryonic tissues and the activity of MnSOD in the heart ( < 0.004) as well as relative liver weight ( < 0.05) under normal incubation temperature but also decreased ( ≤ 0.05) embryo mortality and HSP90 mRNA level in the liver and heart of embryos. Furthermore, under high incubation temperature, maternal diet Mn supplementation increased ( < 0.002) MnSOD protein expression in the liver of embryos but had no effect ( > 0.43) under normal incubation temperature. These results indicated that high incubation temperature induced self-protective responses of chick embryos with a modification of antioxidant status and a depression of HSP70 protein level. Maternal dietary supplementation of Mn could improve the hatchability as well as antioxidant ability to protect against heat challenge in embryos during incubation.

Effects of environmental temperature and dietary manganese on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders.

An experiment was conducted to investigate the effects of environmental temperature and dietary Mn on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders. A completely randomized factorial design involved 2 environmental temperatures (a normal temperature, 21 ± 1°C, and a high temperature, 32 ± 1°C) × 3 dietary Mn treatments (a Mn-unsupplemented corn­soybean meal basal diet or the basal diet supplemented with 120 mg of Mn/kg of diet as either MnSO4·H2O or manganese proteinate). There were 6 treatments with 6 replicates (4 birds per replicate). High temperature decreased egg weight (P < 0.0001), laying rate (P < 0.0001), egg yield (P < 0.0001), feed intake (P < 0.0001), egg:feed ratio (P < 0.0001), eggshell strength (P < 0.05) and thickness (P < 0.0001), plasma triiodothyronine level (P < 0.05), and alkaline phosphatase activity (P < 0.04) whereas it increased rectal temperature (P < 0.0001); plasma malondialdehyde level (P < 0.02); and activities (P < 0.002) of lactic dehydrogenase, aspartate aminotransferase, and creatine kinase. Broiler breeders fed the diets supplemented with Mn regardless of source had greater (P < 0.05) eggshell strength and lower (P ≤ 0.05) plasma triiodothyronine level and protein carbonyl content than those fed the control diet. The broiler breeders fed the diet supplemented with the organic Mn had greater (P < 0.01) eggshell thickness than those fed the control diet. There were interactions (P < 0.05) between environmental temperature and dietary Mn in laying rate, egg yield, feed intake, and egg:feed ratio. Under normal temperature, dietary Mn did not affect the above 4 parameters; however, under high temperature, broiler breeders fed the diet supplemented with the organic Mn showed greater (P < 0.03) improvements in these 4 parameters than those fed the control diet. The results from this study indicated that high temperature significantly impaired egg production performance and eggshell quality and induced lipid peroxidation and tissue damage whereas dietary supplementation of either organic or inorganic Mn improved eggshell strength and thermotolerance and reduced protein oxidation and that the organic Mn could alleviate the negative effect of high temperature on egg production performance of broiler breeders at the period of 32 to 45 wk of age.

Neither intact nor hydrolyzed soy proteins elicit intestinal inflammation in neonatal piglets.

BACKGROUND: Efficacy of feeding hydrolyzed soy proteins to infants intolerant to cow milk proteins has not been determined fully. This study compared growth and intestinal responses of neonatal piglets fed formulas with hydrolyzed soy protein to piglets fed formulas with intact soy or cow milk (casein-whey) proteins. METHODS: Piglets (n = 40, day 2 postpartum) were fed commercial milk replacer until day 7 postpartum (designated day 0) and then were assigned randomly to casein-whey (CW) or soy (intact, SI; hydrolyzed SH) formulas to evaluate intestinal responses on days 0, 2, 5, and 10. RESULTS: Average daily gain was higher for CW (121 g/d; p < .05) compared with SI piglets 85 g/d); SH pig weight gain was intermediate (109 g/d). Villus height-to-crypt depth ratio in proximal jejunum was lower (p < .05) on day 2 than day 0 in soy-fed pigs and lower (p < .05) on day 5 than day 0 in CW pigs. Mucosal mast cells were generally higher in CW pigs compared with soy-fed pigs. Villus goblet cell numbers in the midjejunum of SH-fed piglets were lower (p < .05) on day 5 compared with day 0. On day 5, crypt goblet cell numbers were higher (p < .05) in the midjejunum of CW-fed piglets compared with SH-fed piglets with numbers intermediate for SI-fed piglets. Intestinal differences were not detected among dietary treatments for major histocompatibility complex class I and II gene expression, tissue concentrations of prostaglandin E2, or CD8+ T-cell numbers. CONCLUSIONS: Hydrolyzed soy proteins do not elicit intestinal inflammatory responses in piglets and may be viable alternatives to milk and intact soy proteins for feeding infants.

Urinary excretion of taurine as a function of taurine intake: potential for estimating taurine bioavailability in the adult cat.

Urinary taurine excretion increases markedly when excess taurine is consumed. Experiments were designed to characterize this response in an attempt to develop an assay system for taurine bioavailability in common cat foods using an adult cat model. Initial studies investigated the time course of changes in urinary taurine excretion in response to alterations in taurine intake. The rate of urinary taurine excretion decreased rapidly when cats were switched from a casein diet supplemented with 0.2% crystalline taurine to a diet containing no supplemental taurine, reaching steady-state in 2 d. In contrast, urinary taurine excretion by cats switched from low to high taurine did not plateau until 6 to 7 d. Subsequently, cats (n = 18) were fed a casein diet containing graded levels of crystalline taurine (0, 0.025, 0.05, 0.10, 0.15 or 0.20%). After a 7-d adjustment period, urinary taurine excretion was quantified over a 5-d collection period and also by cystocentesis, and blood taurine levels were measured on d 6. Plasma taurine increased linearly (r = 0.88) as taurine intake increased, while whole-blood taurine increased asymptotically, reaching 95% of maximum concentration at a taurine intake of 93 mu mole/(kg body weight.d). The rate of urinary taurine excretion increased only slightly as taurine intakes increased to 96 mu mol/(kg body weight.d), but increased markedly (15-fold) thereafter. The same pattern was observed whether urinary taurine excretion was expressed as mu mole/(kg body weight.d) from total urine collection or as mu mole/g creatinine from cystocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Utilization of medium-chain triglycerides by neonatal pigs: effects of emulsification and dose delivered.

Four trials were conducted using 86, 24-h-old pigs to evaluate the utilization of medium-chain triglycerides (MCT). Effects of emulsification and amount of MCT fed were examined. After a 4-h period during which feed was withheld, pigs were force-fed MCT (containing 75% octanoate and 25% decanoate), marking time 0 of the experiment. Blood samples were obtained at 1 and 2 h for subsequent medium-chain fatty acid (MCFA) analysis. In Trials 1 (six pigs/treatment) and 2 (four pigs/treatment) the response to three emulsifying agents was compared to a nonemulsified (NE) control. Twenty milliliters of a 30% (vol/vol) emulsion of MCT or 6 mL of NE MCT was administered. Concentrations of MCFA at 1 h in pigs receiving a Tween 80 (polyoxy-ethylene [20] sorbitan monooleate) emulsion were 3- to 19-fold higher than concentrations in animals administered a gum arabic/gum tragacanth emulsion, a lecithin emulsion, or NE MCT. Trials 3 (eight pigs/treatment) and 4 (six pigs/treatment) were conducted to determine the plasma MCFA concentrations resulting from feeding increasing levels of NE (3, 6, 9, or 12 mL of MCT) or emulsified MCT oil (2, 4, 6, or 8 mL in a 30% Tween 80 emulsion). Plasma octanoate concentrations measured at 1 h increased linearly (P < .05) with increasing MCT dosage through 9 mL of NE and 6 mL of emulsified MCT. A transient narcosis was observed in 8 of 12 animals that received 6 or 8 mL of emulsified MCT and was most pronounced 1 to 2 h after feeding, which roughly corresponded to peak plasma MCFA concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Emulsification and fatty-acid chain length affect the utilization of medium-chain triglycerides by neonatal pigs.

Three experiments were conducted using 52 pigs between 22 and 35 h of birth to determine the effects of emulsification and fatty-acid chain length on utilization of medium-chain triglycerides (MCT). After a 4-h period during which feed was withheld, pigs were force-fed 6 mL of nonemulsified (NE) MCT or 20 mL of a 30% (vol/vol) Tween 80-(polyoxy-ethylene [20] sorbitan monooleate) MCT emulsion, marking time 0, and serial blood samples were drawn throughout 8 h for analysis of medium-chain fatty acid (MCFA) concentrations by HPLC. In Exp. 1, pigs received either NE or emulsified Tri-C4, -C5, -C6, or -C7. The emulsified treatments were discontinued due to deaths caused by coma resulting from high concentrations (up to 12 mM) of plasma MCFA. Concentrations in pigs fed emulsified MCT were 2.5-fold higher than those in pigs fed NE MCT. In pigs fed NE MCT, concentrations of even-chain-length MCFA were higher than those of odd-chain-length MCFA (P < .001), with a tendency for C6 to be higher than C4 (P < .1). In Exp. 2 and 3, pigs received an equimolar mixture of MCT in either emulsified or NE form. In Exp. 2, the mixture contained Tri-C4 through Tri-C7; whereas, in Exp. 3 the mixture contained Tri-C4, -C6, -C8, and -C10. A three-way interaction (emulsion x fatty acid x sample time; P < .05) was observed in both experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Intestinal effects of milkborne growth factors in neonates of agricultural importance.

Reduction of postnatal morbidity and mortality of mammalian neonates poses a significant challenge to agricultural and medical sciences. Because nutritional insufficiency and diarrhea represent major stressors, an understanding of factors mediating postnatal growth and development of the gastrointestinal tract is essential. This review explores the role that milkborne growth factors may play in stimulating functional development of the neonatal intestine, with emphasis on the porcine, bovine, and ovine species. Studies reporting milk concentrations and intestinal effects are reviewed, with emphasis on epidermal growth factor, insulin, and the insulin-like growth factors. Collectively, these studies suggest that milkborne growth factors may provide important regulatory signals to the neonatal intestine under both normal and pathophysiological states.

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.

Dietary medium- or long-chain triglycerides improve body condition of lean-genotype sows and increase suckling pig growth.

In a field trial conducted on a commercial swine farm, lean-genotype sows (n = 485) were fed diets containing 0 or 10% supplemental fat as either medium-chain triglyceride or choice white grease from d 90 of gestation until weaning (15.5 d). Effects on standard sow and litter production traits were examined together with assessment of sow body condition using live ultrasound. Daily feed intake during lactation was 10% higher in sows consuming diets without added fat (7.2 vs 6.5 kg; P < 0.01); however, lactation ME (23.9 Mcal/d) and digestible lysine (54 g/d) intakes were unaffected (P > 0.10). Sows supplemented with fat were 4 kg heavier on d 109 of gestation (220 vs 224 kg; P < or = 0.01), 1 d after farrowing (210 vs 214 kg; P < or = 0.01), and at weaning (210 vs 214 kg; P < or = 0.01). Expressed as overall gain, this amounted to a 23% increase (0.66 vs 0.86 kg/d; P < or = 0.01) and was accompanied by a 49% increase in backfat (0.82 vs 1.68 mm; P < or = 0.03) from d 90 to farrowing. Changes in sow weight (-0.01 kg/d) and backfat (+4.2 mm) over lactation were minimal and were not affected by fat supplementation (P > or = 0.10). Longissimus muscle area at weaning was slightly greater (44.96 vs 46.2 cm2) in sows consuming fat than in control sows (P < or = 0.05), but changes in longissimus muscle area were not significant from d 90 to weaning (P > or = 0.10). Gestation length, pigs born alive, average birth weight, survival (d 3 to weaning), and days to estrus were not affected by diet (P > 0.10). However, supplemental fat increased pig ADG (192 vs 203 g/d; P < 0.01) and average pig weaning weight (4.3 vs 4.5 kg) at 15.5 d (P < or = 0.02). No differences between the two fat sources were detected. This large-scale study demonstrated that supplemental fat during gestation and lactation effectively improved sow condition and improved suckling pig performance without affecting energy intake during lactation, implying improved efficiency of sow energy utilization.

Hydrogenated dietary fat improves pork quality of pigs from two lean genotypes.

Pork quality is influenced by nutrition, genetics, management, and pork-processing procedures. Pigs of lean genotype fed diets high in unsaturated fat may have thinner, lower-quality bellies with a soft fat composition. Therefore, we investigated the effects of supplementing 5% choice white grease that had been chemically hydrogenated to iodine values of 80, 60, 40, or 20 on pork quality. Diets were fed to barrows and gilts of two genotypes (NPD [Ham-line x Manor hybrid] and PIC [406, 419, or 420 x C22]; n = 240) in a 4 x 2 x 2 factorial design. Pigs (76.8 kg of mean initial weight) were placed on test at a common age and were fed dietary treatments for 52 d. Pigs of PIC genotype were heavier at trial initiation, had higher feed intake and feed conversion ratio (F/G; P < 0.05), and greater backfat (26.3 vs. 24.0 mm; P < 0.001) and loin depth (59.0 vs. 55.3 mm; P < 0.001) compared with the NPD genotype pigs. As the iodine value of dietary fat was reduced, belly thickness increased (P < 0.05) and length decreased linearly (P < 0.05). Congruently, belly fat iodine value decreased from 73.9 to 67.4 (linear effect; P < 0.001) and belly fat C18:2 concentration declined from 20.6 to 16.3% (linear and quadratic effect; P < 0.001). The belly mono- and polyunsaturated fat ratio increased 29% as diet iodine value declined from 80 to 20 (linear and quadratic effect; P < 0.001). Further, there was a linear increase (P < 0.001) in saturated fatty acid concentration of belly fat (C14:0, C16:0, and C18:0) as dietary fat iodine value declined. Quadratic (P < 0.005) effects were detected in the level of C18:1trans as iodine value decreased from 80 to 20, paralleling dietary content. Dietary fat iodine value did not affect fat digestibility, ADFI, or F/G. Pork belly quality was improved as defined by reduced iodine value, C18:2 content, increased saturated fatty acid content, increased thickness, and decreased length as dietary iodine value decreased. Results indicate that reduction of dietary fat iodine value by chemical hydrogenation has the desirable effect of improving pork quality and does not alter growth performance.

Effect of feeding a milk replacer to early-weaned pigs on growth, body composition, and small intestinal morphology, compared with suckled littermates.

Feeding of milk replacer to early-weaned pigs was evaluated in two experiments. In Exp. 1, 18 litters of pigs were either weaned conventionally (d 21), split-weaned and fed milk replacer plus starter diet (d 14 and 21), or weaned and fed milk replacer plus starter diet (d 21). Split weaning combined with feeding a milk replacer increased ADG 22% from d 14 and d 28 compared to conventional weaning (P < .05). Feeding a milk replacer plus starter diet after weaning increased ADG 30% between d 21 and 28 compared to conventional weaning (P < .01). In Experiment 2, four litters of 12 pigs each were divided at d 18 into six heavy and six light pigs and randomized across sow-suckled, milk replacer, or starter diet groups. After 1 wk, pigs fed milk replacer weighed 20% more (P < .001), contained 10% more protein (P < .01) and 17% more fat (P < .05), and had 74% longer villi in the proximal small intestine (P < .001) than suckled pigs. In contrast, pigs fed starter diet weighed 19% less (P < .001), contained 20% less protein and fat (P < .001), and had 28% shorter villi in the proximal small intestine (P < .05) than suckled pigs. Therefore, milk replacer feeding the 1st wk after weaning stimulates pig development, both locally in the small intestine and on a whole-body basis, most likely by an increased energy and nutrient intake. Suckling beyond 18 d postnatally inhibits pigs to reach maximal potential weight gain. In conclusion, milk replacer feeding might be beneficial to reach maximal pig weight gain at weaning.

Effect of nutritional status, age at weaning and room temperature on growth and systemic immune response of weanling pigs.

Two experiments were conducted to determine the effect of nutritional status, age at weaning and room temperature on growth and immune response of pigs. In the first experiment, 72 pigs were weaned at either 2 or 3 wk and fed either a complex, simple-adequate or simple-inadequate diet for a 24-d period. Total antibody (TAb) titers in response to injections of human red blood cells (RBC) on either 0, 4, or 16 d postweaning were not affected by age at weaning or dietary treatments even though the nutritional status was compromised to such an extent that pigs fed the simple-adequate diet gained at one-half the rate (.172 vs .349 kg/d) of pigs fed the complex or simple-adequate diets (P less than .01). In Exp. 2, the immunological response of 144 pigs weaned at 3 wk were evaluated at 4 and 8 d postweaning. Pigs were weaned into rooms that averaged either 25 or 18 C, and were fed either a complex or simplex-adequate diet at either ad libitum (AL) or restricted (Res) levels for a 24-d period. Restriction of either the complex or simple diet for the first 16 d of the trial drastically reduced (P less than .01) the growth rates of Res pigs compared with AL pigs (.042 vs .236 kg/d). There were no differences in skinfold thickness (Sf) or TAb, 2-mercaptoethanol sensitive (MEs) and resistant (MEr) antibody titers when pigs were inoculated with phytohemagglutinin-P (PHA-P) or RBC at 4 d postweaning regardless of room temperature, diet source or feeding level.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of soybean oil and dietary copper on ruminal and tissue lipid metabolism in finishing steers.

An experiment was conducted to determine the effects of Cu and soybean oil (SBO) supplementation on ruminal and tissue lipid metabolism and carcass characteristics in finishing steers. Sixty Angus steers (369.0 +/- 10.1 kg) were stratified by weight and randomly assigned to treatments in a 2 x 2 factorial arrangement, with factors being 0 or 20 mg of supplemental Cu/kg DM from Cu sulfate and 0 or 4% SBO. Steers were fed a high-concentrate basal diet that contained 5.3 mg Cu/kg DM. Average daily gain and feed intake were reduced (P < 0.01) by SBO but were not affected by Cu. Gain:feed ratio was not affected by treatment. Liver Cu concentrations were higher (P < 0.01) in steers receiving supplemental Cu and lower (P < 0.04) in SBO-supplemented steers. Copper supplementation tended to reduce (P < 0.12) and SBO supplementation tended to increase (P < 0.11) serum cholesterol concentrations. Backfat depth was reduced (P < 0.10) by Cu and SBO supplementation. Marbling scores and longissimus muscle lipid content were not affected by Cu supplementation; however, SBO supplementation reduced (P < 0.01) marbling scores. Longissimus muscle polyunsaturated fatty acids tended to be increased (P < 0.14) in Cu-supplemented steers. Longissimus muscle C18-conjugated dienes and the 18:1 trans isomer were increased (P < 0.05) in SBO-supplemented steers. Ruminal fluid 18:3 was increased (P < 0.05) and the 18:1 trans isomer was decreased (P < 0.05) in Cu-supplemented steers. These results indicate that as little as 20 mg of supplemental Cu/kg DM can reduce backfat and may alter lipid metabolism in steers fed high-concentrate diets.

Effects of dietary copper source and concentration on carcass characteristics and lipid and cholesterol metabolism in growing and finishing steers.

We conducted an experiment to determine the effects of dietary copper (Cu) source and level on carcass characteristics, longissimus muscle fatty acid composition, and serum and muscle cholesterol concentrations in steers. Sixty Angus and Angus x Hereford steers were stratified by weight and initial liver Cu concentration within a breed and randomly assigned to treatments. Treatments consisted of: 1) control (no supplemental Cu); 2) 20 mg Cu/kg DM from Cu sulfate (CuSO4); 3) 40 mg Cu/kg DM from CuSO4; 4) 20 mg Cu/kg DM from Cu citrate; 5) 20 mg Cu/kg DM from Cu proteinate; and 6) 20 mg Cu/kg DM from tribasic Cu chloride. A corn silage-soybean meal-based diet was fed for 56 d. Steers were then switched to a high-concentrate diet. Equal numbers (n = 5) of steers per treatment were slaughtered after receiving the finishing diets for either 101 or 121 d. Serum cholesterol was not affected by treatment during the growing phase but was decreased (P < .05) in steers supplemented with Cu by d 84 of the finishing period and remained lower (P < . 05) at subsequent sampling periods. Longissimus muscle cholesterol concentration tended to be reduced (P < .11) by Cu supplementation. Hot carcass weight and backfat were lower (P < .05) in animals receiving supplemental Cu. However, Cu-supplemented and control steers had similar marbling scores. Longissimus muscle polyunsaturated fatty acid concentrations (18:2 and 18:3) were increased (P < .07) and saturated fatty acid concentrations tended (P < . 11) to be reduced by Cu supplementation. These results indicate that as little as 20 mg of supplemental Cu/kg diet can reduce backfat and serum cholesterol and increase muscle polyunsaturated fatty acids in steers fed high-concentrate diets.