Effect of fiber source and particle size on chick performance and nutrient utilization.

The addition of fiber in chick feeds is known to dilute nutrients; as a result, this may reduce nutrient digestibility and performance. However, recent studies suggest that moderate inclusion of insoluble fibers (2 to 3%) may stimulate gizzard development, which could result in better nutrient utilization and chick growth. The previous fiber sources evaluated were subject to wide fluctuation in their nutritional and chemical composition due to variation in processing. Miscanthus giganteus is a C4 grass purposefully grown for its fiber content which has a consistent fiber composition compared to food process residues. The objectives of this study were to determine the effect of dietary fiber source and particle size on day-old chick performance and nutrient digestibility. Day-old chicks (8 chicks per cage, 5 cages per treatment) were fed diets containing 3% of either sepiolite (SEP), cellulose (CEL), coarse beet pulp (BP), fine BP, coarse Miscanthus grass (MG), and fine MG. At the end of days 7, 14, and 21, chicks and experimental diets were weighed to compute average daily gain and feed intake. In addition, excreta from the previous 48 h of each data capture point was collected to determine nutrient digestibility. In general, chicks fed diets containing fiber consumed more feed, gained more weight, and had better feed conversion rate than birds fed the SEP diet. Particle size of the fiber had no effect on chick performance; however, nutrient utilization was higher (P < 0.05) for chicks fed coarse fiber particles compared to these fed fine fiber particles. Birds fed diets containing MG performed similar to chicks fed CEL (P > 0.05), but digestibility coefficients of birds fed BP diets were generally higher than chicks fed MG diets. In conclusion, chicks performed better with fiber in their diet and MG was comparable to CEL.

The amino acid composition and protein quality of various egg, poultry meal by-products, and vegetable proteins used in the production of dog and cat diets.

New protein ingredients are used to support pet food market growth and the development of new products while maintaining animal dietary needs. However, novel protein sources (e.g., spray-dried chicken, and (or) rice, pea, and potato protein concentrates) have limited data available regarding their protein quality. The objective of this study was to evaluate protein ingredients used in the pet food industry by laboratory analysis and a chick growth assay as a model. Following analysis for proximate and amino acid composition, chicks (six birds per pen with four pens per treatment) were fed experimental diets for 10 d. Diets contained 10% crude protein from each of the experimental protein sources (spray-dried egg-SDEG; spray-dried egg white-SDEW, spray-dried inedible whole egg-SDIE, chicken by-product meal-CBPM, chicken meal-CKML, low-temperature fluid bed air-dried chicken-LTCK, low-temperature and pressure fluid bed dried chicken-LTPC, spray-dried chicken-SDCK, whey protein concentrate-WPCT, corn gluten meal-CGML, corn protein concentrate-CPCT, potato protein isolate-PPIS, rice protein concentrate-RPCT, pea protein isolate-PEPI, soy protein isolate-SPIS, and soybean meal-SBML) along with an N-free diet (negative control). Chicks fed SDEG, SDIE, and LTPC had the highest protein efficiency ratio (PER; P < 0.0001; 5.18, 5.37, and 5.33, respectively), LTCK and SDCK were intermediate (4.54 and 4.79), and the CBPM and CKML were the lowest among the poultry proteins for EAA:NEAA, PER, and Lys availability. Among the vegetable proteins, PPIS and SBML had the highest PER values (3.60 and 3.48, P < 0.0001). In general, the chick PER method ranked the quality of animal protein sources higher than vegetable proteins, and these results were consistent with the EAA:NEAA ratio and Lys availability.

Comparison of 3 agar media in Fung double tubes and Petri plates to detect and enumerate Clostridium spp. in broiler chicken intestines.

Clostridium perfringens is an anaerobic, spore-forming bacterium that may lead to necrotic enteritis, resulting in poor feed efficiency and increased mortality in chickens. It is estimated that C. perfringens infects almost 1 million people in the United States every year. The objective of this research was to compare the Fung double tube (FDT) and conventional Petri plates using 3 different media to detect and enumerate Clostridium spp. in chicken intestines. Nine Cobb 500 broilers were randomly selected and euthanized at 21 and 42 d of age for a total of 18 samples. The jejunum and ileum from each broiler were harvested and studied in 2 methods and 3 media combinations, utilizing a 2 × 3 factorial totaling 6 treatments. The 2 methods were FDT and conventional Petri plates, and the 3 media were Shahidi-Ferguson Perfringens (SFP) with egg yolk supplement, polymyxin B, and kanamycin (E); SFP with polymyxin B and kanamycin (P); and SFP with d-cycloserine (C). Enumerations were performed after 24 h of incubation at 37°C. At 21 d, counts using medium C with FDT (4.51 log10 cfu/g) and plates (2.38 log10 cfu/g) were higher (P < 0.05) than using media E or P. On d 42, there were no differences among plate treatments and medium E had the highest counts (0.98 log10 cfu/g). Of all the FDT, medium C (5.35 log10 cfu/g) had the highest counts (P < 0.05), followed by medium P (3.54 log10 cfu/g). This study illustrates that the FDT method is able to enumerate Clostridium spp. at higher levels (P < 0.001) than the conventional Petri plate method; therefore, the FDT should be implemented and further explored.

Ruminal degradability and lysine bioavailability of soybean meals and effects on performance of dairy cows.

Evaluations of 4 soybean meal (SBM) products were conducted in 3 experiments. The 4 products were 1) solvent SBM (SSBM), 2) SSBM treated with 0.05% baker's yeast and toasted at 100 degrees C (YSBM), 3) expeller SBM (ESBM), and 4) lignosulfonate-treated SBM (LSBM). Multiparous Holstein cows (n = 32; 152 +/- 63 d in milk; body weight = 708 +/- 77 kg; producing 41 +/- 7 kg/d of milk at the beginning of the study) were used in a 4 x 4 Latin square design with 28-d periods to investigate cow responsiveness to supplemental ruminally undegradable protein (RUP) from the SBM products. Dietary treatments were formulated by substituting all of the SSBM and part of the ground corn with YSBM, ESBM, or LSBM to yield isonitrogenous diets. Diets were formulated to provide adequate ruminally degradable protein, but deficient RUP and metabolizable protein supplies. No differences among dietary treatments were observed for dry matter intake, body weight gain, milk and component yields, or efficiency of milk production. The lack of response to changes in SBM source was likely due to an adequate RUP and metabolizable protein supply by all the diets. In situ ruminal degradations of YSBM and LSBM were slower than those of SSBM or ESBM; thus, RUP contents of YSBM and LSBM were greater than those of SSBM or ESBM. The RUP of all SBM products had similar small intestinal digestibility. Available Lys contents, estimated chemically or by using a chick growth assay, were less for YSBM and LSBM than for SSBM or ESBM, suggesting deleterious effects of processing on Lys availability in YSBM and LSBM.

Protein quality of various raw and rendered by-product meals commonly incorporated into companion animal diets.

Several experiments were conducted to evaluate the protein quality of various raw and rendered animal by-product meals commonly used in companion animal diets. Six freeze-dried raw animal meals (beef lungs, pork lungs, sheep lungs, pork livers, oceanfish, chicken necks) and 3 rendered animal meals (lamb meal, regular ash poultry by-product meal, and low ash poultry by-product meal) were fed in chick assays to determine Lys and TSAA bioavailability, protein efficiency ratio (PER), and net protein ratio (NPR). Each experimental diet was offered to 4 replicates of 5 chicks per pen in all growth assays. Furthermore, each animal by-product meal was fed to mature White Leghorn roosters for determination of true AA digestibility. All freeze-dried, raw animal meals were offered to 5 replicate roosters, and all rendered animal meals were offered to 4 replicate roosters. Most raw animal meals exhibited moderate to high protein quality. Lysine bio-availabilities ranged from 86 to 107% and 70 to 99% for raw and rendered animal meals, respectively. Bio-availability of TSAA ranged from 64 to 99% and 61 to 78% for raw and rendered animal meals, respectively. The PER values ranged from 2.83 to 4.03 and 2.01 to 3.34 for raw and rendered animal meals, respectively. The NPR values ranged from 3.83 to 4.8 and 3.05 to 4.12 for raw and rendered animal meals, respectively. Despite a numeric increase in NPR vs. PER values, the overall ranking of animal meals remained similar. Lamb meal had the poorest PER and NPR values, and pork lungs had the greatest values. Total essential AA digestibility and total AA digestibility ranged from 93.6 to 96.7 and 90.3 to 95.5%, respectively, for raw animal meals and 84.0 to 87.7 and 79.2 to 84.8%, respectively, for rendered animal meals. Rendered animal meals generally had lower protein quality than raw animal meals, with lamb meal consistently having the poorest protein quality and pork livers having the greatest protein quality.

Environmental fate of roxarsone in poultry litter. I. Degradation of roxarsone during composting.

Roxarsone, 3-nitro-4-hydroxyphenylarsonic acid, is an organoarsenic compound that is used extensively in the feed of broiler poultry to control coccidial intestinal parasites, improve feed efficiency, and promote rapid growth. Nearly all the roxarsone in the feed is excreted unchanged in the manure. Poultry litter composed of the manure and bedding material has a high nutrient content and is used routinely as a fertilizer on cropland and pasture. Investigations were conducted to determine the fate of poultry-litter roxarsone in the environment Experiments indicated that roxarsone was stable in fresh dried litter; the primary arsenic species extracted with water from dried litter was roxarsone. However, when water was added to litter at about 50 wt % and the mixture was allowed to compost at 40 degrees C, the speciation of arsenic shifted from roxarsone to primarily arsenate in about 30 days. Increasing the amount of water increased the rate of degradation. Experiments also suggested that the degradation process most likely was biotic in nature. The rate of degradation was directly proportional to the incubation temperature; heat sterilization eliminated the degradation. Biotic degradation also was supported by results from enterobacteriaceae growth media that were inoculated with litter slurry to enhance the biotic processes and to reduce the concomitant abiotic effects from the complex litter solution. Samples collected from a variety of litter windrows in Arkansas, Oklahoma, and Maryland also showed that roxarsone originally present had been converted to arsenate.

Research notes: passive integrated transponder tags as markers for chicks.

Passive integrated transponder (PIT) tags have been used to mark a variety of organisms and have potential for marking poultry chicks. We examined the effects of PIT tags subcutaneously implanted in 3- and 7-d-old Leghorn chicks and found no significant differences over 40 d in survival or rate of daily body mass gain among tagged chicks and controls. The PIT-tagged birds were not more susceptible to pecking by other chicks than controls. No birds died, but 1 of 20 chicks lost its tag during the study. We believe that PIT tags provide a viable technique for marking individual juvenile birds, if tag loss can be reduced. Costs may be prohibitive in studies involving large numbers of birds.

Identification of an insulin response element in the fatty acid synthase promoter.

We have previously reported that insulin increases fatty acid synthase (FAS) gene transcription, and that sequences responsible for positive regulation are located within the first 332 base pairs of the FAS promoter. To define minimal sequences required for insulin regulation within this region, chimeric constructs containing serial 5' deletions starting at -318 and extending through position +67 of the rat FAS gene ligated to the luciferase reporter gene were transfected into 3T3-L1 adipocytes. Insulin treatment at 10 nM increased luciferase activity 2-3-fold in 3T3-L1 adipocytes transfected with constructs containing progressive deletions from -318 to -67. This stimulation of the FAS promoter activity by insulin was dose-dependent. However, no effect of insulin was observed when fusion constructs containing FAS promoter sequences spanning from -25 or from -19 to +67 were transfected into adipocytes. These results suggest that the insulin response sequences of the FAS gene may be located in the region from -67 to -25. DNase I footprinting using liver nuclear extracts revealed a protected region spanning -71 and -50 in addition to a region near the putative TATA box. Gel mobility shift assays using the sequence from -71 to -50 as a probe revealed nuclear factor(s) from mouse liver and 3T3-L1 adipocytes that specifically complexed with this sequence. Mutational analysis of this region showed that sequences between -68 and -60 are essential for recognition and interaction with a trans-acting factor(s). Moreover, when three tandem repeats of the sequences spanning -68 to -52 were linked to the SV40 promoter and used for transfection, luciferase activity increased 3.6-fold in response to insulin treatment. Thus, we have identified novel cis-acting DNA sequences responsible for insulin regulation of the FAS gene, which interact with nuclear protein(s) from liver and adipocytes and which are found to share limited homology to insulin response sequences present in other genes.

The hypocholesterolemic agent dichloroacetate increases egg cholesterol content of laying hens.

Experiments were conducted to determine whether a diet with added dichloroacetate (DCA), an inhibitor of cholesterol biosynthesis, would influence plasma and egg cholesterol concentrations when fed to laying hens. In the first experiment, 62-wk-old laying hens (10 hens per treatment) were fed a control diet containing 0, 350, 700, or 1,400 ppm DCA for an 8-wk period. Egg production and size, feed intake, weight gain, and plasma and egg cholesterol were determined at biweekly intervals. In a second experiment, 36-wk-old laying hens (eight hens per treatment) received diets with 0, 3,000, or 6,000 ppm added DCA for a period of 6 wk. Production parameters and cholesterol measurements were conducted as in Experiment 1. Egg production and feed intake were significantly decreased with increasing levels of DCA in Experiment 1. In the second experiment, 6,000 ppm DCA sharply reduced feed intake, body weight, and egg production. Yolk weight and percentage yolk were significantly decreased by the higher levels of DCA used in Experiment 2. Total plasma cholesterol was not affected by dichloroacetate in either of the experiments. In contrast, egg cholesterol concentration increased by 10 and 37% in Experiments 1 and 2, respectively, in response to diets with added DCA when compared with the unsupplemented controls. Total egg cholesterol increased in response to dietary DCA in Experiment 1, but not consistently in Experiment 2 due to the decreased yolk size of the hens fed DCA. The results of these studies indicate that dietary DCA was not effective in reducing egg cholesterol concentrations.

Regulation of fatty acid synthase gene transcription. Sequences that confer a positive insulin effect and differentiation-dependent expression in 3T3-L1 preadipocytes are present in the 332 bp promoter.

We have previously reported induction of fatty acid synthase (FAS) gene expression by insulin and adipocyte differentiation in 3T3-L1 cells. In order to identify sequences responsible for insulin regulation of the FAS gene, chimaeric constructs containing serial deletions of the 5'-flanking region of the rat FAS gene ligated to the chloramphenicol acetyltransferase (CAT) reporter gene were prepared and transfected into 3T3-L1 cells. Plasmids containing 2100 (-2100CAT), 1400 (-1400CAT), 1009 (-1009CAT) and 332 (-332CAT) bp of FAS 5' flanking sequences exhibited comparable basal CAT activities in 3T3-L1 preadipocytes. This activity was 3-fold higher when these constructs were transiently transfected into 3T3-L1 adipocytes. Stably transfected 3T3-L1 cells also exhibited a 3-fold increase in CAT activity upon adipocyte differentiation, indicating that sequences required for the differentiation-dependent increase in FAS expression are located within the 332 bp promoter. Treatment with 10 nM insulin increased CAT activity by 2.1 +/- 0.2-, 2.6 +/- 0.1-, 2.0 +/- 0.2- and 1.7 +/- 0.2-fold respectively in 3T3-L1 adipocytes transiently transfected with -2100CAT, -1400CAT, -1009CAT and -332CAT plasmids. CAT activity was increased by 3.0 +/- 0.3- and 3.5 +/- 0.6-fold respectively by insulin treatment in adipocytes stably transfected with -2100CAT and -1009CAT plasmids. When insulin-responsive H4IIE hepatoma cells were transiently transfected with -2100CAT, -1400CAT, -1009CAT and -332CAT plasmids and then treated with 10 nM insulin, CAT activity increased by 3.1-, 3.1 +/- 0.8-, 3.0 +/- 0.7- and 2.3 +/- 0.5-fold respectively in serum-free media, and by 2.6 +/- 0.4-, 3.3 +/- 0.9-, 3.1 +/- 0.4- and 2.9 +/- 0.6-fold respectively in the presence of 0.5% serum. These results indicate that sequences responsible for insulin regulation of FAS gene are also located within 332 bp of the transcription start site.

Reduced plasma cholesterol and lipoprotein in laying hens without concomitant reduction of egg cholesterol in response to dietary sorbose.

Experiments were conducted to determine the effect of sorbose on feed consumption, egg production and size, and cholesterol metabolism of laying hens. In Experiment 1, 87-wk-old laying hens (10 per treatment) were fed diets containing 0, 10, or 20% sorbose for 4 wk. In a second experiment, 108-wk-old laying hens (eight per treatment) were fed a control diet, a diet with 10% added sorbose, or the control diet with intake restricted to the level of sorbose-treated hens for 4 wk. Feed consumption and egg production were recorded daily. Plasma and egg cholesterol levels were determined at 0, 2, and 4 wk. Plasma and egg very low density lipoprotein (VLDL) concentrations were determined after 4 wk. Egg production, feed intake, and body weight gain were significantly reduced by dietary sorbose. Egg and yolk weight and percentage yolk decreased in response to sorbose. Sorbose significantly reduced plasma cholesterol and VLDL by approximately 50%, compared with the hens fed a control diet. Egg cholesterol concentration (milligrams per gram of yolk) was significantly increased, although the reduction in yolk size resulted in similar total egg cholesterol (milligrams per egg). Restricting feed intake of laying hens significantly lowered plasma cholesterol, but not to levels comparable to that of sorbose-treated hens. The data indicate that substantial reduction of plasma cholesterol and VLDL by dietary sorbose was not accompanied by reduced egg cholesterol.

Growth and tissue lipid deposition of broilers fed alpha-ketoisocaproic acid.

Dietary alpha-ketoisocaproic acid (KIC) was studied for effects on growth, feed efficiency, tissue cholesterol (TC) content, and immune response to a Newcastle disease virus (NDV) vaccination in broilers. In two experiments, broiler chicks were fed diets supplemented with graded levels of KIC to .54% of the diet. Feed efficiency, fat deposition, BW gain, and plasma cholesterol levels were determined at 3 wk. In a third experiment, broilers were fed diets supplemented with 0, .1, .2, and .4% KIC throughout the starter (0 to 3 wk), grower (3 to 6 wk), and finisher (6 to 7 wk) periods. Abdominal fat and plasma and breast TC were measured at 7 wk. In Experiment 4, levels of KIC to .6% were fed to broilers to determine TC content and to measure the immune response to NDV vaccination. Feed efficiency, BW gain, and percentage abdominal fat were not affected by KIC in any of the broiler experiments. The addition of KIC to broiler diets resulted in a significant reduction in breast (Pectoralis major) TC. Biceps (Biceps femoralis) TC, adductor (Pubo-ishio-femoralis) TC, and plasma cholesterol content was not affected by KIC. Geometric mean titers to NDV were not improved by KIC. The data indicate that KIC has no effect on growth or abdominal fat deposition, but may have a role in TC homeostasis.

Cholesterol concentration of egg yolk and blood plasma and performance of laying hens as influenced by dietary alpha-ketoisocaproic acid.

Experiments were conducted to determine the effect of supplemental alpha-ketoisocaproic acid (KIC) or Leu on layer performance and plasma and egg cholesterol levels. In the first experiment, 0, .09, or .27% KIC and .09 or .27% Leu were fed to 62-wk-old laying hens. In a second experiment, the same levels plus another level of .54% KIC and .54% Leu were fed to 32-wk-old hens for an 8-wk period. The basal diet or the basal diet supplemented with .27% KIC or .27% Leu were continued for 20 wk to determine the long-term effects of these supplements. In a third experiment, hens were fed 0, .1, .2, or .4% KIC for 8 wk. The addition of KIC and Leu to the hen diets did not affect percentage egg production, egg weight, shell thickness, or Haugh units. In Experiment 1, .27% KIC and .09% Leu significantly increased BW gain. Neither KIC or Leu significantly affected BW gain in Experiment 2 when measured at 8 or 28 wk. In the third experiment, diets supplemented with KIC increased significantly BW gain. In Experiment 1, .09% KIC and .09% Leu significantly reduced egg cholesterol at 4 wk. After 8 wk, .27% KIC reduced egg cholesterol significantly below the controls. No effect on plasma or egg cholesterol was observed in Experiments 2 and 3.

Influence of orotic acid on performance, liver lipid content, and egg cholesterol level of laying hens.

Three experiments were conducted to determine the effects of dietary orotic acid (OA) on laying hen performance, liver lipid content, and plasma and egg cholesterol levels. Laying hens were fed a basal diet supplemented with 0, .5, 1.0, and 2.0% OA for 8 wk. Performance of the hens and cholesterol levels were measured at biweekly intervals. In all three experiments, OA decreased (P less than .05) BW in a linear manner. In two experiments, OA caused a linear decrease in total liver lipid (P less than .05), and in a third experiment OA resulted in a quadratic effect (P less than .01) on liver lipid content. There were no effects observed by OA supplementation on egg weight, yolk weight, percentage yolk, or egg production. Orotic acid failed to influence egg cholesterol content in any of the biweekly measurements of the three experiments. In two experiments, total plasma cholesterol content was not influenced by OA supplementation. Orotic acid significantly reduced (P less than .05) free and total plasma cholesterol in a third experiment when measured at Weeks 4, 6, and 8 of the experiment. The data indicate that OA is an ineffective dietary supplement for reducing egg cholesterol levels in laying hens.

Dietary and monensin effects on activity of hepatic microsomal mixed function oxidase system in chickens.

Four experiments were conducted to investigate if the degree of activation of the microsomal mixed-function oxidase (MFO) system was related to the degree of growth depression associated with the addition of monensin to the diet. The experiments were conducted with broiler chicks in battery brooders in which the chicks were fed diets of various composition and containing monensin at 0 to 160 ppm. In all experiments, the activity of the MFO system was estimated by the change in the content of cytochrome P-450 in the hepatic microsomes. Activities of some microsomal enzymes were also measured in some of the experiments. Feeding a diet with 24% protein containing fish meal, alfalfa meal, and torula yeast significantly increased the activity of the MFO system in comparison with feeding an isonitrogenous and isoenergetic corn and soybean diet, but there was no difference between the diets in the toxicity of monensin as measured by growth rate. Supplementing a 16% protein but not a 24% protein diet with monensin significantly reduced growth rate. In none of the four experiments was there a statistically significant change in the hepatic content of cytochrome P-450 as a result of feeding monensin. Thus, variation in the magnitude of growth depression caused by monensin in diets of different protein concentration or ingredient composition does not appear to be explained on the relative degree of the activation of the MFO system.

Large-scale overproduction and rapid purification of the Escherichia coli ssb gene product. Expression of the ssb gene under lambda PL control.

We report a rapid procedure for the large-scale purification of the Escherichia coli encoded single-strand binding (SSB) protein, helix-destabilizing protein which is essential for replication, recombination, and repair processes in E. coli. To facilitate the isolation of large quantities of the ssb gene product, we have subcloned the ssb gene into a temperature-inducible expression vector, pPLc28 [Remaut, E., Stanssens, P., & Fiers, W. (1981) Gene 15, 81-93], carrying the bacteriophage lambda PL promoter. A large overproduction of the ssb gene product results upon shifting the temperature of E. coli strains which carry the plasmid and also produce the thermolabile lambda cI857 repressor. After 5 h of induction, the ssb gene product represents approximately 10% of the total cell protein. The overexpression of the ssb gene and the purification protocol reported here enable one to isolate SSB protein (greater than 99% pure) with final yields of approximately 3 mg of SSB protein/g of cell paste. In fact, very pure (greater than 99%) SSB protein can be obtained after approximately 8 h, starting from frozen cells in the absence of any columns, although inclusion of a single-stranded DNA-cellulose column is generally recommended to ensure that the purified SSB protein possesses DNA binding activity. The ability to easily purify 1 g of SSB protein from 300-350 g of induced cells will facilitate physical studies requiring large quantities of this important protein.