Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “feed conversion ratio”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2001

The effect of discontinuing the use of antimicrobial growth promoters on the productivity in the Danish broiler production.

On 15 February 1998, the Danish poultry industry voluntarily decided to discontinue the use of all antimicrobial growth promoters (AGPs). To investigate how the removal of AGPs influenced the broiler productivity in Denmark, data from 6815 flocks collected from November 1995 to July 1999 by the Danish Poultry Council were analysed. The three flock parameters were: kilogram broilers produced per square meter (per rotation), feed-conversion ratio (total kilogram feed used per rotation/total kilogram live weight per rotation) and total percent dead broilers ((number of dead broilers during the rotation/number of broilers put in the house per rotation)x100). Data were analysed using a mixed model, allowing the correlation structures in the data to be taken into account. The analyses showed that kilogram broilers produced per square meter and percent dead broilers in total were not affected by the discontinued use of AGPs. However, the feed-conversion ratio increased marginally 0.016 kg/kg and has remained at this level throughout the rest of the study period.

Animals↗
PubMed2005

Evaluation of a diet free of animal protein in germfree swine.

BACKGROUND: Two experiments were conducted in which germfree pigs or pigs monoassociated with Lactobacillus paracasei subspecies paracasei were fed either a traditional milk-based diet (Esbilac) or an experimental diet free of animal protein (DFAP). METHODS: Throughout the 16-day study, animals' clinical condition, total weight gain, feed conversion, and bacterial contamination were monitored. At the conclusion of the study the animals were killed, necropsied and tissues sampled for L. paracasei isolation. RESULTS: General pig disposition remained consistent between treatment groups and trials, except for two animals that developed mild diarrhoea during trial 1. All pigs remained viable during the study irrespective the diet fed or probiotic inoculation. Germfree pigs fed the Esbilac diet gained on average a total of 1034 +/- 63.0 g, and had a feed conversion ratio of 0.17 +/- 0.01 g of gain per 1 ml of diet. Germfree pigs fed the experimental diet gained on average a total of 599 +/- 151 g, and had a feed conversion ratio of 0.10 +/- 0.02 g of gain per 1 ml of diet. Monoassociated pigs fed the Esbilac diet gained on average a total of 862 +/- 70.3 g, and had a feed conversion ratio 0.14 +/- 0.01 g of gain per 1 ml of diet. Monoassociated pigs fed the experimental diet gained on average a total of 563 +/- 96.8 g, and had a feed conversion ratio of 0.09 +/- 0.02 g of gain per 1 ml of diet. Lactobacillus paracasei established extensively in pigs fed either the Esbilac or experimental diets. Lactobacillus paracasei had no effect (P >0.05) on piglet growth and did not display any interactions based on the diet fed. Measured growth parameters were statistically different (P <0.05) based on the diet fed and variance seen between trials. CONCLUSION: In conclusion, a DFAP has been developed and has been shown to be capable of sustaining life in piglets up to 16 days of age.

Animal Feed↗
PubMed1988

Fat deposition in a broiler sire strain. 4. Performance of broiler progeny of four differently selected sire lines.

Cocks from four lines selected for a low amount of abdominal fat (AF), a favorable feed conversion ratio (FC), and high body weight after restricted (GR) or ad libitum (GL) feeding were mated to commercial broiler breeder hens. A total of 3,600 broiler progeny in three hatches from these matings was reared by line in litter pens. At 41 days of age GR and GL line progeny had significantly heavier body weights, poorer feed conversion ratio, and higher percentages of abdominal fat than AF and FC line progeny. At comparable body weights (AF, 1,893; FC 1,918; GR, 1,848; and GL, 1,897 g) feed conversion was most favorable for FC line progeny (1.72), AF and GL line progeny did not differ (1.77), and GR line progeny had the poorest feed conversion ratios (1.79). The AF line progeny had the lowest percentage abdominal fat (1.88%), followed by FC line progeny (2.20%), GL line progeny (2.91%), and GR line progeny (3.10%). As in the pure lines, selection for body weight after restricted feeding was not effective in obtaining leaner and more efficient chickens. When compared with differences between pure lines, results of the broiler progeny matings indicate that body weight, feed conversion, and percentage abdominal fat are inherited largely in an additive manner.

Abdomen↗
PubMed2000

Production performance and pruritic behaviour of pigs naturally infected by Sarcoptes scabiei var. suis in a contact transmission experiment.

Reports on the effects of mange on the production performance of pigs are conflicting. So far, studies have used experimental infections, by depositing encrusted lesions from chronically infected pigs into the ears of experimental pigs. However, this is a poor representation of what happens under natural field conditions. The purpose of our study was to quantify the effects of sarcoptic mange on production performance and pruritus in pigs that were infected by contact with S. scabiei var. suis-infected pigs. A total of 80 piglets were matched by sex and weight and randomly divided between experimental and control compartments. In the experimental compartment, each of three naturally S. scabiei var. suis-infested pigs were randomly allocated to three pens with 13 susceptible pigs each. From day 0 to 35, the growth performance of pigs in the experimental compartment was significantly (P=0.04) worse (35 g/d) than of pigs in the control compartment. From day 35 to 112, there was a statistical trend (P=0.10) that the growth performance of pigs in the experimental compartment was lower (50 g/d) than that of pigs in the control compartment. For the complete fattening period (0-112 or more days), the growth performance of pigs in the experimental compartment was significantly (P=0.05) worse (41 g/d) than that of pigs in the control compartment. Mean feed conversion ratio (kg feed per kg gain) was 2% higher in the experimental compartment compared with the control compartment. Pigs in the experimental compartment had a nine times (95% CI: 2 - 44) higher chance of showing pruritic behaviour than pigs in the control compartment.

Animal Feed↗
PubMed1987

Eggshell quality as influenced by sodium bicarbonate, calcium source, and photoperiod.

The effects of Ca source (limestone or a mixture of one-third limestone and two-thirds oyster shell), NaHCO3 (0 or .5%) and feeding photoperiod (16 or 24 hr) were studied in a 16-week experiment involving 240 Hy-Line W-36 Leghorn hens, 25 weeks of age. Neither egg production (percent hen-day and egg mass, kg egg/bird per 16 weeks) nor feed conversion ratio (kg feed per kg egg) were significantly (P greater than .05) affected by dietary treatment or photoperiod. However, extending the photoperiod to 24 hr significantly (P less than .05) increased feed consumption with a consequent increase in egg weight (P less than .01). Feeding oyster shell in combination with limestone significantly (P less than .05) improved specific gravity of eggs, whereas dietary NaHCO3 significantly (P less than .01) improved elasticity of the egg shell as measured by deformation. Eggshell quality was improved by increasing the photoperiod to 24 hr and was most pronounced when hens were fed diets supplemented with .5% NaHCO3 and limestone as the only source of Ca.

Animals↗
PubMed1988

Distribution of trans and cis 18:1 fatty acid isomers in chicks fed different fats.

The effects of dietary trans isomers of 18:1 (t-18:1) were studied in chicks by feeding purified diets containing soybean oil (SBO) as the control lipid source, saturated fat (SF), hydrogenated soybean oil (HSBO), or spent restaurant grease (SRG) for three weeks. Argentation thin-layer chromatography and gas-liquid chromatography were used to separate trans and cis (c) isomers of 18:1 and to determine the fatty acid composition in chick tissues. Chicks fed HSBO (34% t-18:1 of total 18:1) had weight gains similar to those of chicks fed SF but significantly (P less than .05) lower gains than those of chicks fed SBO or SRG. No differences were observed in feed conversion ratios (total feed:total gain) across treatments. Trans-18:1 was incorporated into liver, heart, lung, and abdominal fat pad of chicks fed HSBO. Chicks fed HSBO had higher levels of c-16:1 omega 7 and 18:1 and lower levels of linoleate and arachidonate in tissue lipids. Similar changes were observed in liver microsomal fatty acids of chicks fed SRG that was adequate in linoleate, but which contained low levels of t-18:1 (4% of total 18:1). Positional and geometrical isomers of 18:1 appear to impair essential fatty acid metabolism in the chick.

Adipose Tissue↗
PubMed2003

Continuous disinfection as a means to control infectious diseases in poultry. Evaluation of a continuous disinfection programme for broilers.

A full continuous disinfection programme, consisting of disinfection during cleanout of poultry houses prior to placement of chickens, disinfection of the drinking water and spray disinfection of the birds during production was evaluated in broilers under experimental condition as well as under field conditions. Under controlled conditions, the experimental design consisted of three groups, two of which were control groups. Each group comprised 300 chickens. In one of the control groups, no disinfection of the pens was undertaken prior to the placement of the chickens. In the other control group, disinfection of the pens prior to placement of the birds was carried out using a glutaraldehyde-based product. In the test group, disinfection prior to placement was done. The drinking water of these birds was treated continuously and the birds were sprayed with a non-toxic disinfectant during production. Production parameters, such as growth rate, feed conversion ratio and feed consumption, of the birds in the three groups were monitored. In addition, all mortalities in the different groups were recorded and classified into diseases of an infectious nature, non-infectious nature and unknown category. Bacterial counts were also done on a weekly basis from the different pens. In this experiment, it was shown that the full continuous disinfection programme resulted in a lower number of mortalities caused by infectious agents as well as a reduction in the bacterial counts in the pens treated with the full continual disinfection programme. The full continuous disinfection programme was also tested on a commercial poultry farm in the Northern Cape Province of South Africa. Two production houses of 3,500 birds were randomly selected as test houses for the full continuous disinfection programme. Another similar house, which received day-old chicks from the same batch as the other two houses, was selected as the control house; it received the routine disinfection procedure prior to placement of the chicks. During the course of this experiment, a severe outbreak of Newcastle disease was experienced on this farm. It was demonstrated that, in the face of this severe challenge, the full continuous disinfection programme controlled the spread of the disease in both the houses where it had been applied at a stage when in every other house (including the control house) on the farm birds were suffering very high mortalities.

Animal Husbandry↗
PubMed2005

Effects of different management factors on broiler performance and incidence of tibial dyschondroplasia.

(1) This study was to determine the effects of two lighting programmes (continuous--24L:0D or intermittent--12L:3(1L:3D)), two feeding programmes (continuous--ad libitum or meal Jeeding--3 h feed:3 h deprivation x 4 times per d) and two ascorbic acid (AA) supplementations (0 or 150 mg/l in water) on broiler performance and incidence of tibial dyschondroplasia (TD). (2) One-day-old male commercial (Ross PM3) broiler chicks (1600) were used. The chicks were randomly divided into 8 treatment groups (2 x 2 x 2) and their replicates (2) replicates per treatment). (3) Intermittent lighting increased body weight and improved feed conversion. Body weight of broilers was decreased by meal feeding. AA supplementation had no significant effect on the body weight and feed conversion ratio. There was no lighting x feeding x supplemental AA interaction for body weight, feed conversion ratio, mortality rate and carcase weight. (4) Supplemental AA improved the cortical thickness of tibiotarsus and decreased the incidence of TD. (5) It was concluded that the application of intermittent lighting in combination with supplementation of 150 mg/l AA is a useful method to reduce TD in broilers without loss of performance.

Animal Feed↗
PubMed2003

Effect of enzyme preparation containing xylanase and beta-glucanase on performance of laying hens fed wheat/barley- or maize/soybean meal-based diets.

1. A commercial enzyme preparation (Quatrazyme HP) containing xylanase and beta-glucanase was examined in two laying hen experiments with wheat/barley- or maize-based diets. The activities of other enzymes were measured also. Starch, cell wall contents and effects of Quatrazyme HP on in vitro viscosity of wheat, barley, maize and soybean meal were determined. 2. In the first experiment, 90 ISA Brown laying hens at 28 weeks of age were given a wheat/barley basal diet with or without 20mg of Quatrazyme HP, which provided 560 and 2,800 IU of xylanase and beta-glucanase/kg diet. In the second experiment, 66 ISA Brown laying hens at 45 weeks of age were given a maize/soybean meal basal diet with or without 20 mg of Quatrazyme HP/kg diet for 9 weeks. Egg production, egg weight, egg mass, feed conversion ratio and change in body weight were recorded as response criteria. 3. There was a significant improvement in feed conversion ratio with enzyme supplementation. Birds given an enzyme-supplemented diet gained 86 g while those fed on the unsupplemented diet lost 103 g of their body weight by the end of the experiment. 4. The enzyme preparation did not affect either egg production, egg weight or egg mass of birds fed on the maize/soybean meal diet. However, a significant improvement in feed conversion ratio was detected. Birds on either the supplemented or unsupplemented diet exhibited an increase in their body weight at the end of the experiment. 5. Addition of xylanase and beta-glucanase decreased in vitro viscosity of wheat, barley, maize and soybean meal. This effect was greater for wheat and barley than for maize and soybean meal. 6. It was concluded that the beneficial effect of using an enzyme preparation containing xylanase and beta-glucanase is not limited to wheat/barley-based diets but also occurs with maize/soybean meal-based diets.

Animal Feed↗
PubMed2005

Calcium requirements of the modern broiler chicken as influenced by dietary protein and age.

Two experiments were conducted to examine the calcium requirements of broiler chickens fed corn-soybean meal diets. Experiment 1 used a 6 x 2 x 2 factorial arrangement and was conducted with broilers in floor pens during the grower phase (19 to 42 d). Diets were mixed with 6 levels of dietary Ca (0.325, 0.4, 0.475, 0.55, 0.625, and 0.9%) and 17 or 23% CP and fed to males and females separately. Experiment 2 was a 6 x 2 factorial design conducted using Petersime battery brooders during the starter phase (0 to 16 d). The same 6 levels of dietary Ca used in experiment 1 were fed separately to each sex, but only at the 23% level of CP. The diets used in both experiments were formulated to contain 0.45% nonphytin phosphorus. In experiment 1, grower chickens did not demonstrate significant body weight gain (BWG) or feed conversion ratio (FCR) response (g of feed per g of gain) to the different levels of Ca at either level of protein. The percentage tibia ash did not respond to increasing Ca levels beyond 0.625% Ca at either protein level. In experiment 2, BWG increased linearly up to 0.55 and 0.625% dietary Ca for males and females, respectively. Feed conversion ratio decreased linearly with increasing dietary Ca up to 0.625% Ca, and tibia ash was highest at 0.9% Ca for both sexes. These results suggest that the current NRC Ca requirements for the broiler starter (1.0%) are sufficient for maximum bone ash, but that Ca requirements for grower birds (0.9%) may be excessive for optimum BWG, FCR, and tibia ash.

Aging↗
PubMed2026

Bayesian Genome-Wide Association Study of Feed Efficiency Traits in Pigs.

Feed efficiency traits are increasingly important in pig production for improving profitability and environmental sustainability. Understanding their genetic basis is crucial for uncovering underlying biological mechanisms and informing selection strategies. In this study, we analyzed residual feed intake (RFI), feed conversion ratio (FCR), and average daily feed intake (ADFI) in 201 animals. Three separate Bayesian GWASs were conducted using 29,844 SNPs in a case-control design, with the lowest and highest 15% of the phenotypic distribution selected as controls and cases (N = 30 per group), respectively, for each trait. The results confirmed the polygenic nature of the traits, identifying 4 SNPs for RFI on Sus scrofa chromosomes (SSC) 3, 13, and 15 with high posterior probability for the direction of their effects; 4 SNPs for FCR on SSC 8, 14, and 17; and 8 SNPs for ADFI on SSC 1, 2, 6, 8, and 11. A candidate gene search identified 41 potential genes involved in diverse biological processes, including feed efficiency, intestinal development, tissue remodeling and integrity, nutrient transport and absorption, metabolic homeostasis, cellular signaling, energy sensing, and neurological regulation. These genes formed a highly interconnected network, highlighting the complexity of feed efficiency and the interplay among multiple physiological, metabolic, and regulatory pathways.

Bayesian analysis↗
PubMed2006

Effect of benzoic acid on growth performance, nutrient digestibility, nitrogen balance, gastrointestinal microflora and parameters of microbial metabolism in piglets.

In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention.

Animal Feed↗
PubMed1992

Barley inclusion and avoparcin supplementation in broiler diets. 1. Effect on small intestinal bacterial flora and performance.

Diets based on barley or corn without avoparcin supplementation were associated with high counts of Clostridium perfringens in the contents of the small intestine of the birds at the age of 2 to 4 wk. The weight gain of birds younger than 2 wk and the body weight of 4-wk-old birds were significantly lower, and the feed conversion ratio at slaughter was significantly higher, in birds on barley diets than in birds on corn diets. The frequency of birds with sticky droppings on Day 21 was significantly higher for barley diets. The number of C. perfringens, and the feed conversion ratio at slaughter were significantly lower but the number of coliform bacteria, weight gain during the 3rd wk, and body weight of 4-wk-old chickens were significantly higher when the diets were supplemented with 7.5 mg avoparcin/kg feed. The effect of avoparcin on the feed conversion ratio was statistically significant only on a barley diet.

Animal Feed↗
PubMed2003

The influence of temperature on the threonine and tryptophan requirements of young broiler chicks.

Two experiments were conducted to investigate the influence of a warm environment (35 degrees C) on the threonine and tryptophan requirements of young broiler chicks from 7 to 18 or 21 d of age. Seven hundred forty (experiment 1) and one thousand eight (experiment 2) 1-d-old Cobb x Cobb straight-run broiler chicks were raised in wire-floored battery brooders in moderate temperature rooms (33 to 34 degrees C). For the first 7 d, all chicks were fed a standard corn-soybean-meal-based crumbled starter diet. On d 7, six chicks each (experiment 1) and eight chicks each (experiment 2) were randomly assigned to individual pens. In experiment 1, chicks were fed a corn-peanut meal basal diet supplemented with six levels of threonine (0.630, 0.651, 0.673, 0.715, 0.758, or 0.800% of the diet). In experiment 2, chicks were fed a corn-corn gluten meal based basal diet supplemented with six levels of tryptophan (0.090, 0.115, 0.140, 0.165, 0.190, or 0.215% of the diet). Each dietary treatment was repeated with three pens in each room and three rooms at each temperature. Three rooms were set at a moderate temperature of 25 degrees C, and the other three rooms were set at a warmer temperature of 35 degrees C. Body weight gain, feed consumption, and feed conversion ratio were measured. The threonine requirements of young broiler chicks were 0.733 +/- 0.016% (R2 = 0.59) and 0.752 +/- 0.046% (R2 = 0.25) for body weight gain, and 0.744 +/- 0.016% (R2 = 0.67) and 0.722 +/- 0.016% (R2 = 0.47) for feed conversion ratio at 25 and 35 degrees C, respectively (broken-line linear model). The tryptophan requirements of young broiler chicks were 0.151 +/- 0.004% (R2 = 0.85) and 0.144 +/- 0.003% (R2 = 0.89) for body weight gain, 0.144 +/- 0.003% (R2 = 0.88) and 0.142 +/- 0.003% (R2 = 0.88) for feed consumption, and 0.146 +/- 0.005% (R2 = 0.76) and 0.127 +/- 0.002% (R2 = 0.94) for feed conversion ratio at 25 and 35 degrees C, respectively. On average, the threonine and tryptophan requirements of broiler chicks at 35 degrees C were very similar to those kept at 25 degrees C.

Aging↗
PubMed2003

beta-Mannanase ameliorates viscosity-associated depression of growth in broiler chickens fed guar germ and hull fractions.

High concentrations of guar meal in broiler chicken diets reduce body weight and feed efficiency. The increased intestinal viscosity that is responsible for reduced measures of performance results from residual guar gum present in guar meal. Two experiments were designed to study the effects of 2 guar meal fractions at 3 different concentrations, germ (0, 5.0, and 7.5%) and hull (0, 2.5, and 5.0%), and the effectiveness of a beta-mannanase at three levels (0, 1x, and 4x; 1x = 1.09 x 10(5) units/ kg) on broiler growth and feed conversion. Growth and performance were measured as a function of intestinal viscosity. Addition of the germ fraction to rations did not reduce body weight, although feed conversion ratio was increased at 7.5% of the diet. Intestinal viscosity also increased significantly at this level. Enzyme addition significantly reduced intestinal viscosity. Due to an interaction that was present between hull and enzyme concentration, each treatment was compared separately. Inclusion of the hull fraction significantly reduced body weight at both levels of inclusion and increased feed conversion ratio at 5% inclusion. Addition of the enzyme significantly increased body weight and reduced feed conversion ratio in diets containing guar hull fractions. Supplementation of beta-mannanase to feeds containing either fraction of guar meal reduced intestinal viscosity and alleviated the deleterious effects associated with guar meal feeding.

Animal Nutritional Physiological Phenomena↗
PubMed1997

[Glycerol supplementation in broiler rations with low crude protein content].

In connection with the utilization of glycerol, which could become available as a by-product of the fuel production from rapeseed the influence of glycerol feeding with rations of low crude protein content was proved. 61 male day old broiler chickens received ad libitum 8 experimental rations based on maize and soybean meal. The experimental design included 3 factors: 15 or 18% CP; supplementation of essential amino acids or not and a content of pure glycerol of 0 or 10%. During the experimental feeding of 23 days body weight gain, feed conversion ratio, N-balance and the intake and excretion of glycerol was obtained. At the end of the trial the utilization of 15N-methionine and the glycerol content of blood plasma, liver and breast muscle was estimated. Due to the low crude protein content of the rations the body weight gain and N-balance was very low (BWG day 1 to 23: 8.6 to 17 g/animal.d; N-balance day 19 to 23: 0.4 to 1.0 g N/animal.d). The supplementation of essential amino acids was the factor with the highest improving effect on the body weight gain, feed conversion ratio and N-balance. Especially at the begin of the trial animals which received 10% glycerol had have an increased feed intake. The excretion of the supplemented glycerol by excreta amounted to 26% of the intake. However, the glycerol content of the rations did not effect body weight gain, feed conversion ratio, N-balance or utilization of 15N-methionine significantly. The assumption of a saving effect on glucoplastic amino acids due to glycerol feeding could not be manifested. In the mean feeding of glycerol elevated the glycerol level in blood plasma in comparison to the basal level up to 23 times (from 0.6 to 13.6 mumol/ml) and in the breast muscle up to 19 times (from 0.4 to 7.5 mumol/g). Nevertheless, these values were lower than the basal level of glycerol in the liver (17.1 to 19.0 mumol/g), which was significantly increased by glycerol feeding to 128%. Regarding the utilization of glycerol as a by-product of the production of renewable fuels it can be concluded that on the basis of the estimated parameters 10% pure glycerol in broiler rations instead of corn starch is without adverse effects.

Amino Acids, Essential↗
PubMed1995

Association of endogenous avian viral and endogenous viral genes with feed conversion and six-week body weight in broilers.

The consistency of the effect of selection on the frequencies of endogenous avian viral (eav) and endogenous viral (ev) specific restriction fragment length polymorphism (RFLP) bands was studied in two broiler lines selected from a single base population and in an F2 population derived from a reciprocal cross of both lines. One broiler line (FC line) was selected for low feed conversion ratio and the other line (GL line) was selected for high 6-wk body weight. In the F2 population, the band frequencies were determined in groups representing separate tails of the distribution of two production traits, namely, low feed conversion ratio between 29 and 42 d of age and body weight at 42 d of age. The F2 population consisted of 288 females belonging to 24 full-sib families. To rule out family effects, the tails for these production traits were composed by either the best or by the worst female performer for each trait in each full-sib family. In total, 29 HindIII-eav, 34 MspI-eav, and 21 BamHI-ev bands could be distinguished by RFLP analysis. This report describes the influence of selection on 11 potentially interesting bands. Two bands, the 9.5-kb HindIII-eav and the 15-kb MspI-eav band, which were found both in higher frequencies in the parental FC line, were also found in higher (P < or = .05) frequencies in the F2 tail with a favorable feed conversion ratio. A third band, the 6.5-kb HindIII-eav band, present in lower frequencies in the parental GL line, was also present in lower (P < or = .05) frequencies in the F2 tail of birds with heavy body weight.

Aging↗
PubMed1996

[Glycerol as a feed ingredient for broiler chickens].

In a first trial glycerol was tested as a feed ingredient for broiler chickens. The influence of glycerol supplementation on weight gain, feed intake, feed conversion ratio and N-balance was proved. 90 Broiler chickens (Lohmann Meat) were fed ad libitum in 6 groups with nearly isoenergetic diets based on corn and soybean meal with 23% crude protein and 0; 5; 10; 15; 20 or 25% pure glycerol in the DM. During a feeding period of 31 days animals had have a very good intake of all experimental diets. The highest weight gains were observed in the groups with 5 and 10% glycerol (34.9 and 35.3 g/animal.d, resp.). However, this effect was not significant compared to the control group (34.3 g/animal.d), but was significant superior to the gain of groups with 20 and 25% glycerol in the diet (30.2 and 26.6 g/animal.d, resp.). The feed conversion ratio was unchanged up to 10% glycerol (1.65 kg/kg gain) and rose to 2.08 kg/kg gain with 25% glycerol. Up to 20% glycerol the N-balance (1.6 to 1.8 g N/animal.d) was positively correlated with the glycerol content in the diet (r = 0.98). The estimation of the plasma glycerol level 2 hours after feeding indicated a remarkable increase already with a 5% supplementation of glycerol from 0.65 (control) to 4.36 mmol/l. Further supplementation caused on average 11 to 54 mmol glycerol/l varying considerably between the individual animals. In general 25% glycerol in the diet caused the lowest performance and pathological changes in the crop epithelium, liver and kidneys. From the point of view of weight gain, feed intake, and feed conversion ratio as well as N-balance a supplementation of 5 to 10% glycerol seems to be beneficial.

Animal Feed↗