Trends to decrease the age of sexual maturity and point of lay without concurrent increases in dietary Ca may reduce the potential for full skeletal mineralization in pullets. During lay, the henâs increased genetic capacity to produce more eggs with less feed without respective increases in dietary Ca may further predispose hens to bone weakness leading to welfare and livability issues. Objectives of this research were to evaluate the effect of feeding increased calcium during rearing and the lay cycle as well as strain and density on laying hen performance and bone mineralization status. Pullets were grown to 16 wks in a grow house with 52 pullets/replicate and 28 replicates/treatment (5,824hens total) which were then moved to a lay house from 18-66 wks with either 24 or 36 hens/replicate (at 48 or 64 sq in) so that there was a total of 26 replicates/treatment (5,728 hens total). The 2 x 2 factorial arrangement of treatments during rearing were Leghorns strain: Hy-Line W-36 (H) and Babcock B-300 (B) and Ca:P ratios: elevated (RC+) Ca:P 2.14, 3.14, 4.14 and control (RC) Ca:P 2.14, 2.14, 2.42 ratio of starter (0-6 weeks), grower (6-12 weeks), and developer (12-17 weeks), respectively. In the lay cycle, the 2 x 2 x 2 x 2 factorial consisted of strain, rearing diet, layer dietary regimens: increasing Ca and P (LC+) and constant (LC) and cage densities: low, 64in2/bird (LD) and high, 48in2/bird (HD). All diets were isocaloric and fed ad libitum. Feed consumption (FC) and BW were monitored bi-weekly (by period) beginning at 2 weeks of age during the rearing and every 4 weeks during the layer phase. Mortality and egg production was recorded daily. During rearing, 5 femurs/trt and during laying, 3 femurs/trt were measured for dry fat-extracted bone weight (DFEW), % ash, volume, and bone breaking strength (BBS) from week 6-16 and from weeks 51-61, respectively. From week 0-17, FC was higher (Pâ¤0.01) when feeding RC+ (5.11 kg) than RC (4.81 kg) otherwise there was no effect on Gain (1,017 and 1,029 g, respectively, P=0.53) or FE (0.199 and 0.214, respectively, P=0.08). Strain had no effect on FC, Gain, or FE. Mortality increased (Pâ¤0.03) by period in the B compared to H strain. Layer performance was not affected by feeding the increased calcium during rearing or lay. Strain effected (Pâ¤0.05) feed consumption, feed efficiency, egg production, and mortality. Feeding more Ca during rearing increased DFEW (RC+=0.94 g vs. RC=0.82 g, P=0.04) while strain effected bone volume (H=2.99 and B=2.37 cc, Pâ¤0.01) and femoral BBS (B=8.55 vs. H=7.80 kg, P=0.01) of pullets. Feeding more Ca during lay did not effect bone status, but feeding it during rearing increased BBS (RC+=14.15 vs. RC=12.37 kg, Pâ¤0.01) in older layers. Strain effected (Pâ¤0.001) both BBS (H=14.26 vs. B=12.26 kg) and volume (H=5.90 vs. B=6.27 cc). These findings indicate that feeding increased Ca during rearing and laying impacts bone mineralization and may be a useful strategy to mitigate bone weakness and such related conditions as cage layer osteoporosis.

The purpose of this research was to compare lemur species and characterize differences that are related to gastrointestinal morphology and physiology. Four lemur species that differ in feeding ecology, V. variegata, E. fulvus, P. verreauxi, and H. griseus, were selected for use in studies designed to focus on key aspects of gastrointestinal morphology or physiology that may differ. V. variegata, a frugivore, and E. fulvus, a generalist, were similar in many respects. Transit time through the gut was rapid (4.03 ± 1.6 h and 3.25 ± 1.6 h; mean ± SE ) and without discernable compartmental slowing. Gastric emptying of 1.5mm radio-opaque spheres (BIPS) was rapid for both species (0.25-0.50 h). Dry matter (DM) (55.5 ± 1.4% and 58.6 ± 1.4%) and insoluble fiber (IF) (19.7 ± 3.4% and 27.7 ± 3.4%) digestibility was low for both by comparison to H. griseus and P. verreauxi. However fecal inoculum from V. variegata fermented soluble fiber substrates (citrus pectin) at a greater rate at 3 h of total short-chain fatty acid fermentation (141.1 ± 12.1 µmol*h-1*g of original substrate (OS) for V. variegata vs. 44.4 ± 12.1 µmol*h-1*g of OS for E. fulvus), suggesting enhanced fermentation of soluble fiber (SF). H. griseus, a bamboo feeder, and P. verreauxi, a folivore, showed similarities, despite large differences in gastrointestinal morphology. The relative tract length compared to body length was 13:1 for P. verreauxi and 4.2:1 for H. griseus but both were equal in DM (72.0 ± 1.4% and 76.3 ± 1.4%) and IF (53.1 ± 3.4% and 62.3 ± 3.4%) digestibility. Within tract transit differed also in that gastric emptying of 1.5mm radio-opaque spheres was delayed (8.0-12.0 h) for P. verreauxi and was more immediate for H. griseus (1.0-2.0 h). TT and MRT of liquid and particle phase markers were also longest for H. griseus. These data add to the body of work available on primate feeding ecology, and also provide novel information useful for the nutritional management of lemurs.

Four experiments were conducted to investigate the effect of short term magnesium supplementation through drinking water prior to harvest on pork quality of pigs. Two days of magnesium supplementation (experiment 1) appeared optimal to improved pork quality. Older, slower growing pigs produced higher pork quality than younger faster growing pigs; however, magnesium supplementation had no effect (experiment 2). The presence of the Halothane and to a greater extent the Rendement Napole mutation reduced the quality of pork (experiment 3). Furthermore, pigs with both mutations had poorer pork quality than pigs with one mutation. Magnesium supplementation reduced pork quality when supplemented to pigs with the Halothane mutation. Pork quality was not affected when dose of magnesium supplemented in the water was altered (experiment 4). Although plasma magnesium was increased by magnesium supplementation, muscle magnesium was not affected. Overall, magnesium supplementation through drinking water for 2 days prior to harvest does not appear to be a method to consistently improve pork quality.

Satellite cells are defined as myonuclear myogenic stem cells residing between sarcolemma and basal lamina of the myofiber. Myofiber number is established during embryonic development. Post-hatch and post-natal muscle growth occurs exclusively through an increase in myofiber size. The increase of myofiber size in early post-hatch turkeys is predominantly dependent on the contribution of new myonuclei to pre-existing myofibers by the mitotically active satellite cell population. Preliminary data in broilers has revealed that supplementation with amino acid deficient diet immediately post-hatch results in an increase satellite cell mitotic activity in Pectoralis thoracicus muscle in 3-day-old chicks as compared to birds fed adequate and above requirement amino acid levels. Additionally, chicks denied feed for first three days post-hatch exhibited significantly lower satellite cell mitotic activity in Pectoralis thoracicus muscle as compared to remaining treatment groups. The hypothesis tested in the current study was that turkeys supplemented with crude protein and amino acid deficient diet early post-hatch would produce higher meat yield at 140 days. Since very little is known about the impact of early nutrition on the satellite cell activity in commercially raised turkeys, the objective of the present study was to measure the effect of different levels of dietary crude protein and amino acids (0.88 NRC, 1.00 NRC, and 1.12 NRC) as well as feed deprivation on the satellite cell mitotic activity, Pectoralis thoracicus muscle weight, and body weight of commercially raised turkey males. At 3, 4, 5, 8, and 11 days of age, birds from each treatment group were injected with 5-bromo-2?-deoxyuridine (BrdU) to label mitotically active cells. The right Pectoralis thoracicus muscle was harvested one hour after BrdU injection followed by BrdU and PI immunohistochemistry and measurement of myofiber diameters. On the third day post-hatch satellite cell mitotic activity was the highest (P<0.05) in 0.88 NRC treatment group and the lowest (P<0.05) in the feed deprived group. On the fourth day post-hatch, feed deprived birds exhibited the lowest (P<0.05) satellite cell mitotic activity and muscle weight. At market age (140 days), there were no significant differences (P>0.05) between treatments in body weight and Pectoralis thoracicus muscle weight. Further evaluation of mechanistic pathways governing satellite cell mitotic activity and muscle growth are necessary to devise early post-hatch feeding strategies that would lead to improvement in Pectoralis thoracicus muscle yield in male turkeys.

Supplements are often fed to stocker cattle on forage-based diets to improve animal performance. Delivery costs can make up a substantial portion of the cost of supplementation. Reducing supplementation frequency can reduce labor and equipment costs and therefore has the potential to increase profit. However, less frequent feeding requires feeding larger quantities of supplement at once and can increase the likelihood of negative associative effects of supplementation. Additionally, little is understood about the metabolic response of ruminants to large fluxuation in nutrient intake. A 50:50 blend of soyhulls and corn gluten feed is widely used by producers to supplement growing cattle. This blend is high in energy but low in starch. It also contains a moderate amount of protein, much of which is ruminally degradable. The purpose of this research was to determine the effect of reducing supplementation frequency of a soybean hull and corn gluten feed blend on performance, digestion, and concentrations of metabolites and hormonal growth regulators in blood of steers. In Experiment 1, growing steers consuming medium quality fescue hay were supplemented either daily, 3 times a week, or 2 times a week. Hay intake was decreased by reducing supplementation frequency but gains were not affected. As a result, the feed to gain ratio increased slightly with less frequent supplementation. In Experiment 2, six ruminally cannulated steers consuming medium quality fescue hay were used in a replicated 3 x 3 Latin square to determine the effect of supplement frequency (daily at 1% BW or on alternate days at 2% BW) on digestion and ruminal parameters. Reducing supplementation frequency decreased hay intake but did not affect digestibility of the diet. On the day of supplementation molar proportions both of propionate and butyrate in the rumen of steers supplemented on alternate days was increased compared to those supplemented daily. In Experiment 3, growing steers were individually fed medium quality hay and supplemented daily (1% BW) or on alternate days (2% BW). Gains did not differ due to supplementation frequency. However, plasma IGF-1 was greater and insulin tended to be greater in steers supplemented less frequently.

Three experiments (EXP) were conducted to determine the potential of experimental sequestering agents, clays or non-digestible yeast oligosaccharides, to reduce milk aflatoxin concentration in lactating Holstein cows consuming aflatoxin. All EXP included two periods in a randomized block design. Cows were fed an aflatoxin-contaminated total mixed ration (TMR) for both periods of all trials. During the first period, cows received no sequestering agents in the TMR, but agents were included in the TMR for the second period. EXP 1 and 2 consisted of two 7 d periods with 12 cows per treatment. Milk aflatoxin (AFM1) concentrations were analyzed by HPLC for milk samples collected on d 5 to 7 and d 11 to 13. Two treatments in EXP 1 were: 1) control (no sequestering agent n=12), and 2) 100g/cow/day Lallemand n=12. Four treatments in EXP 2 were: control (no sequestering agent) n=12, 2) 10g/cow/day MTB-100® (2004) n=12 (Alltech, Inc., Nicholasville, KY), 3) 10g/cow/day MTB-100® 2006 n=12 (Alltech, Inc., Nicholasville, KY) n=12, and 4) 10g/day/cow Alltech experimental (Alltech, Inc., Nicholasville, KY) n=12. EXP 3 consisted of two 8 d periods and included 14 cows. Milk samples from d 4 to 8 and d 11 to 16 were analyzed for AFM1 concentrations by ELISA. Three treatments in EXP 3 were: 1) control (no sequestering agent) n=4, 2) MTB-100® 2006 (Alltech, Inc., Nicholasville, KY) n=5 and 3) Astra-Ben 20A® (AB-20A®) (Prince Agri Products, Inc., Quincy, IL) n=5.For all EXPs, the percent differences in AFM1 concentrations between periods 1 and 2 were calculated. All percent differences were normalized using a correction factor that converted values for controls to zero. The changes from zero (%) due to sequestering agents were considered significant at P < 0.05. In EXP 1, the addition of a mixture of NYO-A and diatomite-montmorillonite resulted in a 5.2% numerical increase in AFM1 concentration. In EXP 2, MTB-100® (2004), MTB-100® (2006), and Alltech experimental product resulted in 8.0%, 6.2%, and 9.5% numerical increases in AFM1 concentrations respectively. In EXP 3, MTB-100® (2006) resulted in a 5.1% numerical decrease in AFM1 concentrations, and AB-20A® resulted in a 60.4% significant decrease in AFM1 concentrations. In summary, the AB-20A® in EXP 3 reduced AFM1 concentrations (P=0.01). There were no significant changes (P>0.25) in AFM1 concentrations in response to sequestering agents other than AB-20A®.

Sixty lactating Holstein cows were used in a replicated block experiment to determine the efficacy of eight feed additives to reduce the transfer of aflatoxin (AF) from feed to milk. Six cows were allocated to each treatment group and 12 to a control group. All cows were fed the same aflatoxin-contaminated total mixed ration (TMR) with either no additive (control) or one of eight additives at 0.5% of the TMR dry matter (DM). Milk samples were collected twice daily to evaluate changes in milk AF concentration, milk AF excretion (milk AF concentration × milk yield); and AF transfer from feed to milk (AF excretion as a percentage of AF intake). All changes were expressed as percentages and calculated relative to the control group which defined zero change. Four of the eight additives resulted in significant reductions (P < 0.05) in milk AF concentration, secretion, and AF transfer ranging from 34.98-40.39%, 36.36-52.28%, and 34.45-48.44%, respectively. Dry matter intake (DMI) was significantly reduced (P < 0.001) by the consumption of AF, while milk production was not affected during the same time period. Neither DMI nor milk production were affected by the addition of treatment products to the diet when compared to control (P > 0.05).

Glycogen stored in liver and muscles are the main energy source during hatching of poultry. Turkey embryos are very sensitive to perturbations in energy metabolism because they have a wider hatching window than chicken embryos. Mortality of turkey embryos during late-term incubation is high relative to chickens, and many surviving hatchlings have compromised vitality. In ovo feeding (IOF) improves the energy status and gut development of perinatal poultry by supplementing the amnion with nutrients, which is then orally consumed by the embryo prior to hatch. A survey of amnion and embryonic development was done to determine the best time, maximum volume and solution characteristics for IOF. Several IOF formulations containing combinations of carbohydrates, proteins and enteric modulators were tested in turkey eggs, with emphasis on comparing hydrolyzed soy protein to egg white. IOF was found to improve energy status at hatch, but subsequent growth performance results were inconsistent. Therefore, further studies were designed to better understand late-term turkey embryo metabolism, using a customized focused oligonucleotide microarray. A gene expression survey using this array was performed on liver, pectoral muscle, hatching muscle, duodenum, and ileum of turkey embryos from 20 days of incubation until hatch. The embryos were found to switch from yolk fat to carbohydrate-based metabolism around 22 days of incubation, and potential substrates were identified to be tested in ovo. A nutritive solution containing metabolic co-factors was then formulated and tested in a subsequent IOF experiment. At hatch, poults treated with this latest IOF formulation exhibited better quality scores and more symmetric legs than controls. Gene expression patterns of liver, pectoral muscle, hatching muscle, duodenum and ileum confirmed IOF favored skeletal development of poults. This dissertation research clearly demonstrated that in ovo feeding technology can enhance energy status and advance the development of hatchlings, resulting in superior poult quality.

Sixty Holstein calves (30 bulls, 30 heifers) were used to examine the effects of supplemental lactoferrin on feed intake, growth, and health during the preweaning and postweaning periods. One of three levels of lactoferrin was added to whole milk in order to produce three dietary treatments: 1.) 0 g/d, 2.) 0.5 g/d, 3.) 1 g/d. Milk (3.8 L/d) was fed from bottles until weaning at 35 days. From days 36 to 56, lactoferrin supplements were added to water (15-25 mL) and fed from bottles. Lactoferrin supplementation did not have any significant effect on feed intake, body weight, average daily gain, heart girth, body temperature, fecal scores, respiratory scores, or haptoglobin concentrations. Calves were housed in individual pens in either an open-sided barn or hutches. Calves raised in the barn consumed more calf starter and therefore grew better than calves raised in hutches. In this study, lactoferrin supplementation was not beneficial. Further research is needed to fully elucidate lactoferrin?s effects in whole milk as well as its role when fed postweaning.

Hepatic â-oxidation and liver and skeletal muscle carnitine palmitoyltransferase I (CPT I) activity and mRNA expression were evaluated in the pig. In the first study, newborn pigs were allotted to one of four dietary regimens: artificial milk replacer with long chain triglycerides (LCT) as the fat source (Control), the Control diet with 0.5% clofibric acid (CA), the Control diet with medium chain triglycerides replacing LCT as the fat source (MCT), or the Control diet with 40 ppm isoproterenol (ISO). There were no differences between Control and MCT or ISO supplemented groups in total, mitochondrial, or peroxisomal â-oxidation of [1-¹⁴C]-palmitate (1 mM). Total and peroxisomal â-oxidation increased 134 and 186%, respectively, with CA supplementation. Hepatic malonyl-CoA sensitive CPT activity increased (p < 0.05) in pigs receiving CA. Changes in relative expression of hepatic LCPT I and skeletal muscle MCPT I mRNA amounts following clofibrate supplementation were not detected, while a modest effect on acyl-CoA oxidase (ACO) relative mRNA amounts was observed (p=0.08). In the second study, hepatic and skeletal muscle CPT I kinetics in pigs during different stages of development were evaluated. Activity of CPT I increased 109 and 67% between birth and 1 wk of age in liver and skeletal muscle, respectively (p < 0.05). Realtive expression of hepatic CPT I mRNA in the 24 hr old pig was 7% of the amount detected in the newborn (p < 0.001); while hepatic CPT I apparent Km for carnitine decreased 48% from birth to 3 wk of age. The apparent Km for carnitine in skeletal muscle decreased from birth to 1 wk of age, then increased 200% between 1 and 5 wk of age (p< 0.01). Plasma and liver free carnitine concentrations increased 200 and 160%, respectively, during the first day of life (p < 0.05). High relative expression of ã-butyrobetaine hydroxylase (ãBBH) in the kidney indicated high capacity for de novo carnitine synthesis by this tissue. Collectively, the findings from this research are important in understanding how the pig, a species with a low capacity for â-oxidation, utilizes fatty acids.