The response of male chicken broilers to the dietary addition of virginiamycin.

Two replicate trials, each involving 400 Arbor Acre male broiler chicks, were conducted to determine the effect of virginiamycin as a growth promoter when added to either the feed or drinking water. A control group received no growth promoter while one treatment group was provided a diet containing 11 mg of virginiamycin/kg. Another treatment group was provided drinking water containing virginiamycin in amounts calculated to ensure equivalent or one-half equivalent intake of the antibiotic. Virginiamycin supplementation had no significant (P greater than .05) effect on mortality or feed conversion ratios, regardless of the mode of administration. Body weights at 21 days of age but not at 42 days of age were significantly (P less than .05) heavier for broilers receiving virginiamycin via the drinking water. The inclusion of virginiamycin in the feed failed to improve body weights at either 21 or 42 days of age.

Effect of lincomycin as a growth promoter for broiler chicks.

1. The effects of adding lincomycin to either the food (2.2 mg/kg) or drinking water (equivalent or 0.5 equivalent amount) of male broiler chicks were examined. 2. There were four treatments: control (no lincomycin), diet containing 2.2 mg lincomycin/kg, control diet plus drinking water containing lincomycin at concentrations calculated to provide an intake equivalent to treatment 2, and treatment 14 with lincomycin concentration reduced by half. 3. There was no significant effect of any treatment upon mortality, efficiency of food utilisation at 42 d of age, final body weights or monetary indices. 4. Analyses of breast, thigh and liver tissues, using a method with a sensitivity of 1.0 mg/kg, failed to reveal any evidence of lincomycin residues. 5. It is concluded that the use of lincomycin at 2.2 mg/kg may not be effective in improving either the biological or economic performance of the broiler chicken.

Omega-3 fatty acid levels and general performance of commercial broilers fed practical levels of redfish meal.

A total of 1,200 day-old Arbor Acre broiler chickens was randomly assigned to 12 pens (50 males and 50 females/pen) and divided into three blocks of four pens each. Each of four different diets was fed ad libitum to one pen of birds within each block to determine the effect of feeding practical levels of redfish meal (RFM) on performance and omega-3 fatty acid content of edible meat and skin lipids of broiler chickens. The four diets included (control) 0%, 4.0%, 8.0%, and 12.0% RFM. Feeding diets containing RFM had no effect on overall mortality or feed efficiency but resulted in decreased incidence of sudden death syndrome and lower body weight (P less than .01) and feed consumption (P less than .05). Additions of RFM to the diets resulted in a substantial dietary enrichment of omega-3 fatty acids (especially eicosapentaenoic acid, EPA or 20:5n-3, and docosahexaenoic acid, DHA or 22:6n-3). Analyses (wt/wt%) revealed that breast meat (less skin) was lower (P less than .001) in lipid and triglyceride but higher in free cholesterol (P less than .001) and phospholipid (P less than .001) than thigh meat (less skin). Dietary treatment had no effect on carcass lipid content or composition. Breast meat lipid contained more (P less than .001) omega-3 fatty acids (especially EPA and DHA), more docosapentaenoic acid, (DPA or 22:5n-3) and more total omega-3 polyunsaturated acids (n-3 PUFA) than thigh meat lipids. Feeding additional RFM resulted in an increased (P less than .001) accumulation of EPA, DPA, DHA, and total n-3 PUFA primarily at the expense of two omega-6 fatty acids, linoleic (18:2n-6) and arachidonic acid (20:4n-6). It can be calculated from the data presented that the consumption of 100 g of chicken that has been fed 12.0% RFM would contribute approximately 197 mg of omega-3 fatty acids (EPA + DPA + DHA) in contrast with the 138 mg of omega-3 fatty acids which would be realized from the consumption of 100 g of white fish such as cod.

Nutritive value of wheat screening as a feed ingredient for broiler chickens.

Data from two experiments, each involving a total of 1,920 (960 males and 960 females) broiler chickens were combined to evaluate the effects of feeding diets containing 0, 15, 30, or 45% ground wheat screenings (WS). Mortality was significantly higher for males than for females at both 21 days (P less than .01) and 42 days of age (P less than .05). Although there was no significant (P less than .05) difference between feed conversion ratios for the two sexes, body weights were significantly higher for males than for females. Significant (P less than .01) dietary effects were evident for feed conversion to 21 days of age but not to 42 days. Dietary effects on body weights were not significant (P less than .05) although a significant linear pattern at 21 days indicated that heavier weights were associated with higher dietary WS levels. Evidence is provided that satisfactory performance can be attained with diets containing up to 45% WS.

Interrelationships among lighting, ambient temperature, and dietary energy and broiler chicken performance.

A total of 4,800 broiler chickens of one commercial genotype were used to study the interrelated effects of two lighting treatments (green fluorescent vs. incandescent), three weekly rates of ambient temperature decline (4.5, 3.5, 2.0 C), and starter/finisher diets with four levels of dietary energy (3,100/3,300; 3,000/3,200; 2,900/3,100; and 2,800/3,000 kcal/kg metabolizable energy). Lighting and ambient temperature treatments had no significant (P greater than .05) effects on percentage mortality, feed conversion ratio, body weight, and monetary return. The highest dietary energy regimens resulted in the heaviest body weights, best feed conversion ratios, and the highest monetary returns. A lighting treatment x diet interaction occurred for female mortality to 42 days but was considered of minor importance. A lighting treatment x diet interaction for feed conversion provided evidence that low temperatures had a more pronounced depressing effect on broiler chickens fed low energy diets. A second order interaction for 42-day male body weights provides evidence that male broiler chickens may be less sensitive to lower ambient temperatures if fed higher energy diets under incandescent lighting compared with those fed lower energy diets under green fluorescent light.

Effect on shell strength of feeding supplemental sources of calcium to adult laying hens given insoluble grit during the rearing period.

1. An experiment was conducted to determine the separate and combined effects of giving insoluble grit during the rearing period and small or large particle size (0.3 mm and 3 to 8 mm in diameter) limestone or oyster shell, as extra sources of calcium, during the laying period. 2. For the entire laying period the extra sources of calcium resulted in improved shell strength but, overall, grit-supplements during the rearing period did not affect either egg shell strength or other performance traits. 3. An analysis for interactions however revealed that limestone of larger particle size coupled with rearing period-grit resulted in improved egg-shell strength during the last quarter of the laying period.

Parental effects on performance of broiler chicken progenies.

Mortality among broiler progeny from a meat-type parent population, consisting of four maternal genotypes (two normal and two dwarf) mated with two normal paternal genotypes (White and Gold) and fed three different breeder diets was not significantly (P greater than .05) affected by genotypes or parental dietary treatments. Body weights of male and female progenies from matings with White males were significantly (P less than .05) heavier at both 21 and 42 days than those sired by Gold males but progeny sired by Gold males exhibited the best feed conversion. The progeny from normal hens were heavier, had a better feed conversion up to 21 days, and yielded higher monetary returns than those from dwarf hens. Parental diets had no significant effect on progeny weights, feed conversion, or monetary returns. A low magnitude first-order interaction, involving paternal and maternal genotypes, occurred for feed conversion and monetary returns.

Effects of light source, ambient temperature, and dietary energy source on the general performance and incidence of leg abnormalities of roaster chickens.

A 2 X 3 X 4 factorial experiment was designed to test the effects of two light sources (incandescent vs. fluorescent), three weekly ambient temperature decrements of 4.5, 3.0, or 1.5 C (from 34.5 to 20 C), and four dietary energy regimens on the general performance and incidence of leg abnormalities of roaster chickens. Light source had no significant effect on mortality, body weight, or feed conversion. Incidence of angular deformity (AD) and total leg abnormalities (TLA) was lower and tibial dyschondroplasia (TD) was higher (P less than .05) for roasters reared under fluorescent as opposed to incandescent light. Cooler ambient rearing temperatures increased (linearly) the incidence of mortality, curly toes (CT), AD, enlarged hocks (EH), and TLA but resulted in a linear decrease in TD and had a detrimental (linear) effect on feed conversion. Dietary energy had no significant effect (P greater than .05) on mortality or leg abnormalities except for CT, (wherein there was decreased incidence with increasing dietary energy) or final live weight, but overall (to 70 days) increasing dietary energy resulted in a linear improvement in feed conversion. Mean monetary returns were nonsignificantly better for roasters reared under fluorescent vs. incandescent light (ca 8 cents/bird) and were better for birds reared under warm versus cool ambient temperatures (ca 10 cents/bird). Increasing dietary energy resulted in a linear increase in monetary returns.

Effects of modified conventional and reverse-protein rearing dietary regimens on the performance of Leghorn hens.

Two commercial Leghorn genotypes were used to study the effects of rearing dietary treatments on juvenile mortality, growth, and adult performance. One control, two modified conventional, and three reverse-protein juvenile dietary regimens were compared. The two genotypes differed in egg production, age at 50% egg production, egg weight, egg specific gravity. Haugh units, and monetary returns. There was no evidence of any genotype X dietary treatment interaction. Juvenile dietary treatments had a significant (P less than .05) effect on body weights at 21 days of age that continued through the juvenile and adult periods to 490 days. Age at 50% egg production, feed efficiency, and initial egg weights were also affected. Although hens reared on one of the modified conventional and two of the reverse-protein regimens returned $.53 per bird more than the remaining three rearing dietary regimens, this difference was not significant (P greater than .05). Evidence is provided that reverse-protein juvenile dietary regimens may support adult performance that equal or surpass the performance of birds reared on conventional dietary programs.

A pneumatic device for attaching wing bands to day-old chicks.

A device for attaching aluminum bands to the wings of day-old chicks is described and illustrated. It is powered with compressed air and utilizes both hand and foot operated controls. Using this device, an operator can apply wing bands without an assistant at rates up to 300 chicks/hour.

Effects of stocking density on the incidence of scabby hip syndrome among broiler chickens.

An experiment, involving 1200 broiler chickens, was conducted to evaluate the effects of stocking density (providing either 840, 720, 585, or 454 cm2 of floor space per bird) on the incidence of scabby hip syndrome at slaughter (42 days). The incidence of scabby hip syndrome was higher at the higher stocking density. Differences were significant for males and approached significance for females (P less than .05). Body weights (42 days) were lower among birds housed at the higher stocking density levels but other traits were not significantly affected (P greater than .05).

Pathological changes associated with the feeding of soybean oil or oil extracted from different rapeseed cultivars to single comb white Leghorn cockerels.

A total of 384 Single Comb White Leghorn cockerels of the Hyline strain were fed either a basal (control) diet containing no added oil or a diet supplemented with 20% by weight of soybean oil, rapeseed oil from cultivars Tower, Candle, a mixture of Echo and Arlo high erucic acid rapeseed (HEAR), or R-500. Levels of erucic acid (22:1) in the rapeseed diets varied from .03 to 10.31%. Three birds from each unit were killed at 28, 56, 84, and 112 days and a wide range of tissues were examined histologically. A number of birds in all dietary groups had healed lesions of avian encephalomalacia. Two cockerels fed HEAR oil and 12 fed R-500 developed marked ascites, firm shrunken livers, hydropericardium, and cachectic muscular atrophy. Marked periacinar necrosis was present in birds dying with ascites. A significantly higher number of birds fed the rapeseed oils developed hepatic sinusoidal distention than birds fed the basal or soybean oil diets. Degenerative myocardial changes were seen only in R-500 and HEAR oil-fed birds. This, coupled with hepatic changes, producing shrunken firm livers, led to development of ascites, cachectic muscular atrophy, and periacinar hepatic necrosis. These changes were probably produced by the high erucic acid content of the HEAR and R-500 oils and the resultant grossly imbalanced diet.

The effect of different totals and ratios of dietary calcium and phosphorus on the performance and incidence of leg abnormalities of male and female broiler chickens.

A factorial experiment involving 1,404 day-old Shaver broiler chicks (702 of each sex) assessed the effects of total calcium (Ca) and available phosphorus (AP) and their ratio (Ca: AP) during the starter (0 to 21 days) and finisher (22 to 42 days) periods on general performance, tibia strength, tibia ash, Ca and P content of tibia ash, tibia dyschondroplasia, twisted legs, and total leg abnormalities. Nine starter and nine finisher diets were used with the percentage Ca and AP ranging from .98 to 1.47 and .39 to .67, respectively, for the starters and from 1.00 to 1.40 and .32 to .51, respectively, for finishers. In general, optimum weight gain, live body weight, feed conversion, tibia strength, tibia dry weight, and tibia ash were obtained when the highest Ca + P was fed, but lower Ca:AP ratios were also effective for some traits. Tibial dyschondroplasia (TD) and total leg abnormalities, however, were highest when these diets were fed. The results indicate that the ratio of Ca:AP in the diet is a determining factor in causing TD in broiler chickens. As the ratio of Ca:AP in the diets widened in response to increased Ca or decreased P, the incidence of TD and total leg abnormalities decreased (P less than .05).

Effect of different levels of dietary sorbic acid on general performance and incidence of leg abnormalities of commercial broilers reared to roaster weight.

Two thousand male, day-old Hubbard chicks were housed in 20 pens (13.5 m2) to evaluate the effects on performance and leg abnormalities of feeding 0, 200, 400, and 600 g/ton dietary sorbic acid during the starter, grower, and finisher periods. These levels of dietary sorbic acid had no significant effect on live body weight, feed conversion, mortality, or the incidence of leg abnormalities of these chicken broilers reared to roaster weight.

Some aspects of the composition of avian ascitic fluid.

Ascitic fluid from male Single Comb White Leghorn chickens fed a diet containing 20% by weight rapeseed oil rich (51.6 weight percent) in erucic (22:1n9) acid contained 2.84 +/- .09 g/dl protein and 2.55 +/- .22 micrograms/ml DNA. A characteristic feature of ascitic fluid as compared to liver and plasma was its high polyunsaturates, low saturates, and low saturate to unsaturate ratio. In general, the fatty acid profile of ascitic fluid is more comparable to the fatty acid profile of plasma lipids than to that of liver lipids. These data suggest that there is no direct absorption of fat and transfer to the ascitic fluid.

The effect of feed denial in starter diets on the performance of broiler chickens.

A total of 2000 commercial chickens (1000 males and 1000 females) were used in an exploratory experiment designed to estimate the effect of two daily feed denial treatments (8 and 12 hr) extended from either 8 to 21 days or 15 to 28 days of age. Mortality was unaffected by these treatments. Body weight at 28 days was reduced, and feed conversion was improved by the feed denial treatments. The length of the daily feed denial period showed a greater impact than age of imposition, and the 12-hr daily denial time diminished the growth performance. At 49 days body weight and monetary returns were higher for the chickens exposed to the 8-hr daily feed denial treatment extending from 8 to 21 days compared with the control group (P less than .10).

Effect of sodium hypochlorite (Javex) on the performance of broiler chickens.

Two separate experiments were carried out with 480 Shaver broiler chicks (240 of each sex) in each, to determine the effects on mortality and biological performance of administering sodium hypochlorite (NaOCl) via the drinking water. The chicks were housed separately (by sex) in Petersime batteries and each experiment began when the chicks were 1 day old and ended when they were 28 days of age. Sodium hypochlorite was added to the drinking water to achieve the following treatment levels (ppm) of available chlorine: 0, 300, 600, and 1200 (experiment 1); 0, 37.5, 75.0, and 150 (experiment 2). Administration of 1,200 ppm available chlorine significantly increased mortality, lowered feed efficiency, reduced water consumption, and lowered heart, liver, kidney, and testes weights. Administration of 300 ppm or more resulted in significantly lower mean body weights. There was some indication of a growth stimulus and improved feed efficiency at the lower concentrations (37.5 to 150 ppm) of sodium hypochlorite administration, but none of the responses was statistically significant. Overall, a significant effect on biological performance or practical benefit was not achieved from administering sodium hypochlorite to broiler chicks.

Effects of feeding vomitoxin contaminated wheat on the performance of broiler chickens.

Two experiments were conducted to ascertain the effect of feeding vomitoxin to meat-type chickens. In each experiment 360 day-old commercial chickens of the Shaver strain were housed in Petersime batteries for 28 days and fed diets containing 0, 12, 24, 36, 48, and 60% of wheat containing 3.00 ppm of vomitoxin. Analysis indicated that the vomitoxin levels in the diets ranged from less than .02 (control) to 1.87 ppm. Each diet was fed in either the all-mash or the crumbled form. There was no evidence of feed refusal or emesis nor were there any significant effects on mortality, body weight gain, live body weight, feed consumption, or feed conversion when these diets were fed. Subjecting the feeds to the pelleting crumbling process had no effect on the level of vomitoxin found in the finished feed. No organ damage from feeding vomitoxin was evident.

The effect of crumbled and pelleted feed on the incidence of sudden death syndrome among male chicken broilers.

An experiment involving 7200 male broiler chickens was conducted to estimate the effect of feeding crumble-pellet diets on the incidence of Sudden Death Syndrome (SDS). Mortality due to SDS was significantly higher for birds fed a crumble-pellet regimen in its usual form or in a ground form compared with birds fed all-mash diets. Birds fed the crumble-pellet dietary regimen grew more rapidly than those on either the ground crumble-pellet regimen or on all-mash. There was no significant (P = .05) difference in the growth rate of the birds fed the ground crumble-pellet regimen compared with those fed all-mash. It was concluded that the higher incidence of SDS was due to some factor(s) in the pelleting process itself rather the rapid growth resulting from the higher density of pelleted feeds.

Growth, heart weight, cardiac lipid, and pathology of chickens fed soybean oil or oil extracted from different rapeseed cultivars.

A total of 384 male Single Comb White Leghorn chicks of the Hyline strain were randomized in 24 Petersime battery units of 16 birds per unit. Four replicate pens were fed either a basal (control) diet containing no added oil or a diet supplemented with 20% by weight of either soybean oil or rapeseed oil (RSO) from cultivars Tower, Candle, Regular, or R-500. Levels of crucic acid (22:1) in the RSO's ranged from .1 to 51.6%. Four birds from each unit were killed at 4, 8, 12, and 16 weeks for cardiac lipid analysis and pathology. Feeding RSO had no consistent effect on body weights, heart weights, or the heart-to-body weight ratio. Only the diet containing R-500 (51.6% 22:1) consistently increased cardiac lipid levels as measured gravimetrically. Maximum deposition of the long-chain monoenes (22:1) and eicosenoic acids (20:1) occurred in the cardiac lipids by 8 weeks, and the levels remained high throughout the 16-week trial. The relative concentration of these long-chain monoenes in the cardiac lipids was positively correlated to the dietary levels of these acids. The incidence of lesions found in heart, liver, and skeletal muscle was significantly higher in chickens fed RSO's high in 22:1 than in chickens fed control or soybean oil, and the incidence significantly correlated to the level of 22:1 in the diet. The incidence of heart and muscle lesions and sinusoidal distention in chickens fed RSO's low in 22:1 was not significantly different from that of chickens fed the control diet or soybean oil, but the incidence of hepatic necrosis was significantly higher for chickens fed RSO's low in 22:1 compared to those fed the control diet or soybean oil.