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PubMed1985

Influence of age, dietary cholic acid, and calcium levels on performance, utilization of free fatty acids, and bone mineralization in broilers.

The effects of age on the utilization of dietary palmitic or a 50/50 mixture of palmitic and oleic acid at the 8% inclusion level in the absence or presence of .2% cholic acid and also in the presence of low (.8%) or high (1.2%) calcium were investigated using broiler chicks from 1 to 56 days of age. Significant interactions (P less than .01) were observed between the type of fatty acid supplemented and the presence or absence of cholic acid on weight gain and feed efficiency. Supplementing diets with a mixture of equal weights of palmitic and oleic acid, reduced feed intake relative to control diets and diets supplemented with palmitic acid alone. There was an interaction between the age of the bird and the type of fatty acid supplemented on fat retention and metabolizable energy (ME) of diets (P less than .01). There was also a significant interaction between the type of fatty acid supplemented and the addition of cholic acid on fat retention and ME of diets. While cholic acid reduced soap formation during the process of digestion (P less than .05), increasing dietary calcium level increased the proportion of the digesta fat that was present as soap (P less than .01). The proportion of digesta and excreta fat, present as soap, depended on the type of fatty acid supplemented. The addition of free fatty acids to broiler diets resulted in a decrease in bone ash and bone calcium content relative to those birds fed the control diet. It is concluded that the ability of broilers to utilize dietary free fatty acids depends on the age at which they are fed, although in all cases supplemental cholic acid enhances fatty acid utilization.

Aging↗

PubMed1994

Dietary L-homoarginine has no lysine bioactivity in chicks.

A chick growth assay was conducted to investigate the effect of dietary L-homoarginine supplementation on performance of chicks fed a Lys-deficient corn-feather meal diet. Weight gain, feed intake, and feed efficiency increased linearly (P < .01) as Lys was added at .1 and .2% from feed-grade L-Lys.HCl. Adding homoarginine at .2% resulted in less (P < .05) weight gain and feed intake than observed in chicks fed the unsupplemented basal diet. These data suggest that dietary homoarginine had no Lys bioactivity, but may also have antagonized Lys utilization from the basal diet.

Animals↗

PubMed1967

Further studies on the use of nicotine to promote leanness in pigs.

Four experiments using weight gain, feed efficiency and carcass analysis criteria were conducted with 148 pigs to determine the effects of feeding nicotine sulfate at various levels on protein and fat deposition. A level of 5 p.p.m. of nicotine sulfate in the ration fed to pigs from weaning until market weight significantly decreased (P<.05) the depth of loin fat in two of three experiments in which it was tested and slightly increased the carcass protein: fat ratio in all experiments. A level of 20 p.p.m. was as effective as 5 p.p.m. but higher levels of 40 and 80 p.p.m. had no effect on carcass quality. The fat content of the livers of pigs fed 5 p.p.m. of nicotine sulfate was found to be 8 to 10 per cent higher than that of controls in the two experiments in which it was measured. Higher levels of nicotine had little or no effect on liver lipids. Plasma cholesterol levels of pigs were not increased by the feeding of nicotine sulfate at levels of 5, 20 and 80 p.p.m.

Animal Feed↗

PubMed1985

The efficacy of salinomycin as a growth promotant for swine from 9 to 97 kg.

Six trials involving 586 pigs initially averaging 9 kg were conducted at three locations (two trials/location) to evaluate the effects of the dietary addition of 0, 27.5, 55, 82.5 and 110 ppm of a monocarboxylic polyether antibiotic, salinomycin, on feed intake, growth rate and feed efficiency of swine fed corn-soybean meal-based diets. Over the total trial (9 to 97 kg), quadratic improvements in gain (P less than .01) and feed:gain (P less than .04) occurred with increasing level of salinomycin, but feed intake was not affected (P greater than .25). Mean improvements for all drug levels over control values for the total trial were 4.3% for daily gain (P less than .01) and 3.4% for feed:gain (P less than .01). For the total trial, rate and efficiency of gain were optimized in pigs fed the 82.5-ppm level of salinomycin with an improvement of 5.2% in daily gain and 4.8% in feed:gain over pigs fed the control diet. The absence of any significant trial X treatment interaction suggests that the nature of the response was not dependent on differences in environment, management or other factors that existed among trial locations.

Animal Feed↗

PubMed2006

Tetracycline residues and tetracycline resistance genes in groundwater impacted by swine production facilities.

Antibiotics are used at therapeutic levels to treat disease; at slightly lower levels as prophylactics; and at low, subtherapeutic levels for growth promotion and improvement of feed efficiency. Over 88% of swine producers in the United States gave antimicrobials to grower/finisher pigs in feed as a growth promoter in 2000. It is estimated that ca. 75% of antibiotics are not absorbed by animals and are excreted in urine and feces. The extensive use of antibiotics in swine production has resulted in antibiotic resistance in many intestinal bacteria, which are also excreted in swine feces, resulting in dissemination of resistance genes into the environment. To assess the impact of manure management on groundwater quality, groundwater samples have been collected near two swine confinement facilities that use lagoons for manure storage and treatment. Several key contaminant indicators - including inorganic ions, antibiotics, and antibiotic resistance genes - were analyzed in groundwater collected from the monitoring wells. Chloride, ammonium, potassium, and sodium were predominant inorganic constituents in the manure samples and served as indicators of groundwater contamination. Based on these analyses, shallow groundwater has been impacted by lagoon seepage at both sites. Liquid chromatography-mass spectroscopy (LC-MS) was used to measure the dissolved concentrations of tetracycline, chlortetracycline, and oxytetracycline in groundwater and manure. Although tetracyclines were regularly used at both facilities, they were infrequently detected in manure samples and then at relatively trace concentrations. Concentrations of all tetracyclines and their breakdown products in the groundwater sampled were generally less than 0.5 microg/L. Bacterial tetracycline resistance genes served as distinct genotypic markers to indicate the dissemination and mobility of antibiotic resistance genes that originated from the lagoons. Applying PCR to genomic DNA extracted from the lagoon and groundwater samples, four commonly occurring tetracycline (tet) resistance genes - tet(M), tet(O), tet(Q), and tet(W) - were detected. The detection frequency of tet genes was much higher in wells located closer to and down-gradient from the lagoons than in wells more distant from the lagoons. These results suggested that in the groundwater underlying both facilities tetracycline resistance genes exist and are somewhat persistent, but that the distribution and potentially the flux for each tet gene varied throughout the study period.

Animal Husbandry↗

PubMed2006

Glucocorticoids exacerbate obesity and insulin resistance in neuron-specific proopiomelanocortin-deficient mice.

Null mutations of the proopiomelanocortin gene (Pomc) cause obesity in humans and rodents, but the contributions of central versus pituitary POMC deficiency are not fully established. To elucidate these roles, we introduced a POMC transgene (Tg) that selectively restored peripheral melanocortin and corticosterone secretion in Pomc mice. Rather than improving energy balance, the genetic replacement of pituitary POMC in PomcTg mice aggravated their metabolic syndrome with increased caloric intake and feed efficiency, reduced oxygen consumption, increased subcutaneous, visceral, and hepatic fat, and severe insulin resistance. Pair-feeding of PomcTg mice to the daily intake of lean controls normalized their rate of weight gain but did not abolish obesity, indicating that hyperphagia is a major but not sole determinant of the phenotype. Replacement of corticosterone in the drinking water of Pomc mice recapitulated the hyperphagia, excess weight gain and fat accumulation, and hyperleptinemia characteristic of genetically rescued PomcTg mice. These data demonstrate that CNS POMC peptides play a critical role in energy homeostasis that is not substituted by peripheral POMC. Restoration of pituitary POMC expression to create a de facto neuronal POMC deficiency exacerbated the development of obesity, largely via glucocorticoid modulation of appetite, metabolism, and energy partitioning.

Animals↗

PubMed1980

Nutrition and management of early weaned pigs: effect of increased nutrient concentrations and (or) supplemental liquid feeding.

Four experiments involving a total of 304 crossbred pigs weaned at 3 to 4 weeks of age were conducted to examine the effect of feeding supplemental liquid milk two to three times daily at weaning and (or) of altering the nutrient composition of the weaning diet. In addition, the effects on postweaning performance of preconditioning young pigs to supplemental milk feeding in the farrowing house were determined. Performance immediately postweaning was poor and was characterized by low weight gains and low feed intakes for approximately 7 days. Increasing the protein and (or) energy concentrations in the weaning diet had no beneficial effect on pig performance in Exp. 1. Feeding supplemental cow's milk three times daily for 4 days postweaning and (or) adding fat to the dry weaning diet also had no beneficial effect on pig performance in Exp. 2. An added milk product to the diet did tend to improve feed efficiency in this experiment. In the third experiment, performance was not affected by supplemental liquid milk feeding three times daily for 7 days and twice daily for an additional 7 days. Additions of 30% nonfat dried milk to the dry diet offered ad libitum did result in improvement in pig performance. Preconditioning of young pigs to supplemental liquid feeding while still nursing the sow resulted in no beneficial response in pig performance immediately postweaning in Exp. 4.

Animal Nutritional Physiological Phenomena↗

PubMed1985

Dietary sodium and chloride levels for growing-finishing pigs.

The performance and the physiological and metabolic consequences of three dietary levels of Na (.03, .09 and .18%) and of Cl (.08, .17 and .32%) arranged factorially were determined in growing-finishing pigs (36 to 89 kg). Average daily gain and feed efficiency of pigs fed .03% Na were lower than pigs fed .09 or .18% Na. Gain:feed ratio of pigs fed .32 or .17% Cl was greater than that of pigs fed .08% Cl during the finishing phase (58 to 89 kg) but not during the growing phase. Increasing dietary Cl levels increased average daily feed intake and gain:feed ratio of pigs fed .03% Na, but had no effect at the higher levels of Na. Plasma Na and Cl were lower (P less than .05) while plasma K (P less than .01), total protein, (P less than .04), albumin (P less than .07) and urea N (P less than .03) were higher in pigs fed .03% Na compared with those fed .09 or .18% Na. Increasing the dietary levels of Cl decreased urea N (P less than .05). Plasma lysine:arginine ratio increased as dietary Cl increased in pigs fed .18% Na diets, but not in pigs fed .03 or .09% Na. The urea cycle intermediate ornithine was highest in the plasma of pigs fed .18% Na. Dietary Na and Cl seem to interact to affect both plasma electrolytes and basic amino acid metabolism.

Amino Acids↗

PubMed1984

Effect of dietary phosphorus level and source on productive performance and egg quality of two commercial strains of laying hens.

An experiment was conducted to study the influence of dietary total phosphorus (TP) level and source on the performance of two strains of commercial layers for two consecutive production years (26 to 68 and 76 to 116 weeks of age, respectively). Diet 1 contained .4% TP; Diets 2, 3 and 4 contained .5, .6, and .7% TP with supplemental P from dicalcium phosphate (DCP); Diets 5 and 6 contained .5 and .6% TP, respectively, with supplemental P from a sample of raw rock phosphate (RRP-1); Diets 7 and 8 contained .5 and .6% TP, respectively, with supplemental P from a second sample of raw rock phosphate (RRP-2). Calcium level was 2.75% in all diets, and crushed oyster shell provided ad libitum to all birds increased the total calcium to about 3.00%. Diet 1 was inferior to the average of all supplemented diets relative to feed consumption rate (P less than .005) and egg weight (P less than .005) during the first year. Diet 1 was also inferior relative to egg production rate (P less than .01), feed consumption rate (P less than .005), and egg weight (P less than .005) during the second year, whereas it was superior in shell quality (P less than .05) during the first year. Increasing TP from DCP resulted in a significant linear increase in feed consumption (P less than .05), feed conversion ratio, and Haugh units (P less than .005). Increasing TP from DCP also resulted in a significant linear decrease in shell quality (P less than .05) and significant linear and quadratic decreases in egg weight (P less than .005) during the first year. During the second year, increasing TP from DCP resulted in a significant linear decrease in egg production rate (P less than .005) and feed efficiency but significant linear (P less than .01) and quadratic (P less than .05) increases in feed consumption, and significant linear and quadratic increases (P less than .005) in Haugh units. Hens receiving RRP diets responded differently during the first and second years. The DCP supported greater egg weight than the RRP during the second year and permitted better feed conversion during both years. Strain A produced larger eggs than Strain B regardless of treatment (P less than .005). When egg production rate and most other response criteria were considered, .5% TP with DCP as the supplemental source gave the best results in both production years. A TP of .6% from RRP-2 gave similar results in both years.

Animals↗

PubMed1987

Effects of feed composition and feeding schedule on growth and development of broiler breeder males.

Two experiments were conducted to compare the effects of feeding broiler breeder males: 1) a 15 or 20% protein starter diet (0 to 4 weeks) and 2) varying levels of energy and protein on an every day (ED) or on an every other day (EOD) basis during the growing period (4 to 20 weeks). Weight gain and shank length at 28 days were less for males started on 15% protein in both experiments. In the first experiment, males fed diets containing 2.8 kcal metabolizable energy (ME)/g during the grower period weighed and gained more than those fed 2.0 kcal ME/g although total ME intake was the same. Males fed ED gained significantly more than those fed EOD. In the second experiment, males fed 15% protein during the grower period gained and weighed more than those fed 12 or 18% protein, and those fed 15% ED gained and weighed significantly more than those fed 20% EOD. In both experiments males fed ED were more feed efficient (as measured by gain/feed consumed) than males fed EOD but consuming the same amount of feed. Semen characteristics were not affected by feeding schedule or grower diet protein level. Fertility was higher in 3 of the 4 weeks sampled for males fed 15% ED. Results indicate that feeding schedule (ED vs. EOD) as well as nutrient intake influence body weight gains of broiler breeder males.

Animal Feed↗

PubMed1990

Anticoccidial effect of monensin against Eimeria mitis and Eimeria dispersa.

Four chick and five poult trials were conducted in order to investigate the anticoccidial efficacy of monensin against Eimeria mitis in chickens and Eimeria dispersa in turkeys. The chicks were fed a basal diet with either 0 or 100 ppm of monensin. The poults were fed a basal diet with either 0 or 60 ppm of monensin. Two days after the initiation of each experiment, the chicks and poults were crop-intubated with oocysts of E. mitis and E. dispersa, respectively. A group was also included that was not infected and not medicated. Growth and feed intake were recorded. At 6 or 7 days postinoculation, the birds were killed by cervical dislocation and were scored for the incidence and severity of intestinal abnormalities. The Eimeria mitis infection reduced (P less than .01) gain and the feed:gain ratio, compared with uninfected birds; the E. dispersa infection only reduced (P less than .05) gain. Although well-defined, discrete lesions were not observed, marked intestinal abnormalities were noted in birds infected with either E. mitis or E. dispersa. Also, the infected, unmedicated birds had increased (P less than .01) intestinal scores compared with uninfected birds or those with infection but treated with monensin. Monensin eliminated the reduction in gain and feed efficiency seen in the infected birds. The infected birds fed monensin had intestinal scores, gain, and feed:gain ratios similar (P greater than .10) to those for the birds that were not infected and that did not receive medication.

Animals↗

PubMed2001

Performance of broilers fed limited quantities of feed or nutrients during seven to fourteen days of age.

Three experiments were conducted with male broilers to study the effects of early life undernutrition. In all studies, treatments were represented by three or four replicate floor pens, each containing 30 to 40 birds. In Experiment 1, broilers were fed at 0.75 kcal ME/gBW0.67 for 4 d, 1.5 kcal ME/gBW0.67 for 5 d or 2.25 kcal ME/gBW0.67 for 6 d, all imposed beginning at 6 d of age. Birds were smaller following feed restriction (P < 0.01) although growth compensation occurred, and at 49 d all restricted birds were heavier (P < 0.01) than full-fed control birds. Improved growth was associated with improved feed conversion (P < 0.01), although carcass composition was unchanged. In a second study, birds were fed at 0.75 kcal ME/gBW0.67 for 3, 4, or 5 d, starting at either 4, 7, or 10 d of age. When feed restriction was applied early, or for shorter periods of time, growth compensation occurred (P > 0.05). With other more severe feed restriction, birds were smaller (P < 0.05) at 49 d compared to controls. Feed conversion was improved following prior feed restriction (P < 0.01, 0 to 49 d). In a third trial, broilers were fed a starter diet diluted with 50% oat hulls. Birds failed to consume enough of this diluted feed, and so were initially smaller. However 49-d weight was not affected (P > 0.05). When periods of 24-h feed withdrawal were imposed in conjunction with the diluted diets, birds were underweight at 49 d. It is concluded that physical feed restriction at 0.75 to 1.5 kcal ME/gBW0.67 imposed for 3 to 4 d in the second week of life currently presents the best option as a means of controlling broiler growth so as to improve feed efficiency.

Adaptation, Physiological↗

PubMed1991

The ability of pigs to control their protein intake when fed in three different ways.

The ability of pigs to control their protein intake was tested in three different ways. When pigs were offered access to single feeds of different protein contents, at a constant liveweight of 20 kg, they increased their daily feed intake as the protein content of their feed was decreased (long-term protein intake regulation). When the protein content of their feed was altered daily, pigs consumed consistently higher amounts of feed when they had access to a low protein feed rather than to a high protein one (short-term protein intake regulation). When, finally, they were given a choice between two feeds of different protein contents, pigs selected a diet that met their protein requirements (as judged by their growth rates and feed efficiencies) and avoided excess of protein intake, but only if they had had previous experience of both feeds. It is suggested that pigs first need to learn about the feeds that are subsequently offered as a choice, before they can make correct dietary choices.

Animal Feed↗

PubMed2000

The effects of growth hormone-releasing peptide-2 (GHRP-2) on the release of growth hormone and growth performance in swine.

The effects of GHRP-2 (also named KP102), a new growth hormone-releasing peptide, on the release of growth hormone (GH) and growth performance were examined in swine. The single intravenous (i. v.) injection of GHRP-2 at doses of 2, 10, 30 and 100 microg/kg body weight (BW) to cross-bred castrated male swine stimulated GH release in a dose-dependent manner, with a return to the baseline by 120 min. The peak GH concentrations and GH areas under the response curves (GH AUCs) for 180 min after the injections of GHRP-2 were higher (P < 0.05) than those after the injection of saline. The GH responses to repeated i.v. injections of GHRP-2 (30 microg/kg BW) at 2-h intervals for 6 h were decreased after each injection. The chronic subcutaneous (s.c.) administration of GHRP-2 (30 microg/kg BW) once daily for 30 days consistently stimulated GH release. The GH AUCs for 300 min after the injections on d 1, 10 and 30 of treatment in GHRP-2-treated swine were higher than those in saline-treated swine. However, chronic administration of GHRP-2 caused a partial attenuation of GH response between d 1 and 10 of treatment. The chronic s.c. administration of GHRP-2 also increased average daily gain for the entire treatment period by 22.35% (P < 0.05) and feed efficiency (feed/gain) by 20.64% (P < 0.01) over the saline control values, but did not significantly affect daily feed intake. These results indicate that GHRP-2 stimulates GH release and enhancing growth performance in swine.

Animals↗

PubMed1980

Re-evaluation of the lysine requirement and lysine utilization by fingerling channel catfish.

Studies were conducted to reassess the lysine requirement for fingerling channel catfish and to evaluate the effects of feeding lysine-supplemented diets. Based on growth studies, utilizing casein and gelatin diets supplemented with crystalline L-amino acids to correspond to the pattern of 30% whole egg protein, the lysine requirement for fingerling channel catfish is approximately 1.5% of the dry diet or 5.0% of the dietary protein which confirms the previously reported lysine requirement. Contrary to prior reports, growth and feed efficiency data from studies using peanut meal diets (formulated to be first limiting in lysine) supplemented with feed grade lysine, demonstrate that fingerling channel catfish are able to utilize free amino acids effectively.

Animals↗

PubMed1982

Comparative utilization of the isomers of phenylalanine and phenyllactic acid by chicks and rats.

A series of experiments was conducted to assess quantitatively the growth-promoting capacity of the isomers of phenylalanine (Phe) and phenyllactic acid (PLA). The slope-ratio procedure was used to determine percent efficacy relative to l-Phe. Addition of the isomers of Phe to a Phe-deficient chemically-defined diet produced linear growth and feed efficiency responses. Only the l-isomer and racemic mixture of PLA elicited a gain or gain:feed response. Efficacy estimates for male chicks were: dl-Phe, 90.1%; d-Phe, 74.6%; l-PLA, 70.1%; dl-PLA, 5.9%. The comparative utilization of d-Phe, phenypyruvic acid (PPA) and l-PLA by chicks was also evaluated when these compounds were fed to male chicks as the sole source of dietary Phe. PPA activity, 84.8%, was slightly greater than that of either d-Phe, 75.3%, or l-PLA, 67.4%. Efficacies of l-PLA and dl-PLA were 46.1 and 28.0%, respectively, d-PLA had no growth-promoting activity for the rat.

Animals↗

PubMed2005

Effects of guar meal by-product with and without beta-mannanase Hemicell on broiler performance.

Guar gum production yields a high protein guar meal that can be subdivided into germ and hull fractions. Feeding high concentrations of guar meal reduces body weight and feed efficiency in chickens due to the presence of a residual guar gum. Two experiments determined the upper feeding levels of guar meal and the hull and germ fractions in broiler chickens. An industrial source beta-mannanase (Hemicell) also was fed in combination with guar meals. Experiment 1 utilized a 3 x 4 factorial design to feed broiler chickens diets containing guar germ, guar hull, or guar meal at 4 levels (2.5, 5.0, 7.5, and 10.0%) compared with a negative control diet. Results indicated that any of the 3 guar meals could be fed at a 2.5% dietary inclusion rate without adversely affecting broiler chicken growth to 6 wk of age. In experiment 2, a 4 x 2 factorial design consisting of the 3 by-products meals at 5% inclusion and soybean meal control with and without enzyme tested whether Hemicell could increase inclusion rates without decreasing broiler growth or feed consumption to 6 wk of age. Addition of Hemicell to feed had no effect on measures of growth in chickens fed the control diet. Hemicell significantly improved feed:gain ratio of diets containing 5% of each fraction of guar meal versus the untreated diets. Feed:gain ratio for the Hemicell-treated 5% germ fraction diet was improved to control diet levels. Results indicated that the upper feeding level of guar meal and germ and hull fraction of guar meal is 2.5%, and addition of beta-mannanase (Hemicell) increases the upper feeding level for the germ fraction to 5%.

Animal Feed↗

PubMed1972

Thiopeptin, a new feed-additive antibiotic: biological studies and field trials.

Thiopeptin is a new antibiotic, produced by Streptomyces tateyamensis and developed solely for animal use as a feed additive. The antibiotic content in animal tissue and feed was assayed in terms of the antimicrobial activity against Mycoplasma laidlawii A. This antibiotic was found to be relatively nontoxic in rats and mice. In chickens, this antibiotic is excreted into feces within 48 hr of administration and is not absorbed in tissue. It is well tolerated in both broilers and swine and is highly stable in animal feed. Thiopeptin-supplemented feed contributes to the improvement of weight gain, feed efficiency in chickens and swine, and the egg performance in layers. Thus, thiopeptin, when used as a feed additive, is quite suitable for supplementing animal nutrition.

Animal Feed↗