Effects of in ovo injection of organic trace minerals and post-hatch holding time on broiler performance and bone characteristics.

Effects of the in ovo injection of organic Mn, Zn, and Cu in association with post-hatch (POH) feed and water restriction on the performance and physical-chemical bone parameters of male Ross × Ross 708 broilers were examined. On 17 d of incubation, a total of 1,872 eggs were subjected to in ovo injection using a commercial multi-egg injector. Treatments (TRT) includingd non-injected and diluent-injected controls. The respective Zn, Mn, and Cu levels (mg/mL) added to the diluent of the low (LMD) and high mineral (HMD) TRT groups were 0.181, 0.087, and 0.010, and 0.544, 0.260, and 0.030, respectively. The 4 TRT groups were then sub-divided into 2 POH holding time (HT) groups, with 15 birds randomly allocated to each of 6 replicate pens in each of the 8 groups. The first HT group (0HT) had immediate access to water and feed, and the second HT group (24HT) contained birds that were kept in transport baskets for 24 h before being released. Performance was determined and selected birds were subsequently necropsied and their tibiae extracted for analysis. In comparison to birds from 24HT group, those in the 0HT group had a higher BW gain and feed intake, and a lower FCR through 21 d POH. The percentage of bone ash of the birds belonging to the HMD group was higher than all other TRT on d 1 POH and was higher than the non-injection control group on d 21 POH. On d 1, the LMD and HMD groups had higher tibial Mn concentrations than those of the control groups. On d 7, bones from the HMD group had a higher concentration of Mn than did the non-injected control group, and likewise, on d 21 POH, had a higher concentration of Zn than did the control groups. In conclusion, a 24HT negatively affected the performance of the birds during the first 2 wk POH; however, the LMD and HMD TRT had a positive influence on bone mineralization.

Effects of commercial in ovo injection of 25-hydroxycholecalciferol on bone development and mineralization in male and female broilers.

Improved bone development and mineralization in broilers have been attributed to the use of 25-hydroxylcholecalceiferol [25(OH)D3] as a dietary supplement. In this study, effects of the in ovo injection of 25(OH)D3 delivered in commercial diluent on 18 d of incubation (doi) on subsequent bone development and mineralization in male and female Ross × Ross 708 broilers were investigated. The variables investigated included bone mineral density and breaking strength, bone ash concentration, and calcium and phosphorus bone ash concentrations. In a single-stage incubator, with 6 treatments on each of the 10 tray levels, a total of 2,400 experimental broiler hatching eggs were evenly and randomly set. Eggs were treatment-injected and transferred to corresponding hatching baskets on 18 doi. Experimental treatment groups were those that received 0.2, 0.6, 1.8, or 5.4 µg of 25(OH)D3 that were delivered in 100 µL of commercial diluent. Noninjected and diluent-injected controls were also included. On 21 doi, chicks were pulled and placed in corresponding floor pens, and on each of d 0, 14, and 28 posthatch (poh), 2 birds of each sex from each pen were randomly selected for necropsy and extraction of both of their tibia bones. Bones from the right leg were subjected to mineral density analysis and those from the left leg were used to determine breaking strength and residual bone ash concentration. Furthermore, ash calcium and phosphorus concentrations on d 14 and 28 poh were determined. There was a treatment × sex × age interaction for bone breaking strength. Bone breaking strength in male birds on d 28 poh was higher in the 0.20, 0.60, and 1.80 µg of 25(OH)D3-injected treatment groups than in the diluent-injected control group. In conclusion, although the in ovo injection of 25(OH)D3 had no positive effect on the bone development of Ross × Ross 708 broilers through d 28 poh compared with noninjected controls, it may provide a benefit to those subjected to an injection of commercial vaccine diluent.

The effect of male and female supplementation of L-carnitine on reproductive traits of white leghorns.

Previous work in our laboratory showed that including 125 ppm of l-carnitine in the diets of roosters increased sperm concentration. The objective of this experiment was to determine whether reproductive efficiency could be improved by feeding l-carnitine to both parents over that of feeding l-carnitine to only the male or female. Diets formulated to contain 0 or 125 ppm of l-carnitine were fed to male and female birds from hatch until 37 wk of age. Eighty-four roosters were used, with the semen of 2 roosters constituting an experimental unit. Pools of semen from either l-carnitine-supplemented or control roosters were artificially inseminated into each of 288 hens with 23.5 muL of semen at weekly intervals, in a 2 x 2 factorial arrangement, resulting in a mean insemination dose of 1.2 and 1.1 x 10(8) sperm/hen for l-carnitine and control hens, respectively. Dietary l-carnitine, as compared with the control diet, increased egg yolk l-carnitine concentration (P = 0.001), decreased hatchling yolk sac weights (P = 0.0001), decreased yolk sac lipid content at hatch (P = 0.01), and culminated in compositional changes of yolk fatty acids, but it did not affect hatch rate, egg production, and egg traits. Although supplementing diets with l-carnitine improved sperm concentration, it did not result in a subsequent improvement in hatch rate, most likely because of the high numbers of sperm that were inseminated artificially in both the control and l-carnitine-supplemented hens. The higher concentrations of l-carnitine in the yolk of hatching eggs obtained from hens consuming l-carnitine as compared with controls may have encouraged the utilization of fat by developing embryos, as indicated by the decreased hatchling yolk sac weights and yolk sac lipid content, perhaps leading to the selective utilization of linoleic (C18:2n-6) and alpha-linolenic (C18:3n-3) acids for growth and development over myristic (C14:0) and oleic (C18:1n-9) acids.

The effect of dietary L-carnitine on semen traits of White Leghorns.

A previous study conducted in our laboratory showed that feeding 500 ppm of dietary L-carnitine to young and aging White Leghorns for 5 wk improved sperm concentration and reduced sperm lipid peroxidation during the last half of supplementation. The current study examined the effect of feeding dosimetric as well as lower levels of L-carnitine for longer durations on semen traits of White Leghorns. In experiments 1 and 2, White Leghorns consumed diets supplemented with 0, 125, 250, or 500 mg of L-carnitine/kg of feed. For experiment 1, an 8-wk trial was conducted with 48 White Leghorns from 46 to 54 wk of age. For experiment 2, a 17-wk trial was conducted with 96 White Leghorn roosters from 46 to 63 wk of age. For experiment 3, 84 roosters were provided for ad libitum consumption a diet formulated to contain 0 or 125 ppm of L-carnitine beginning at hatch until 37 wk of age. Long-term consumption of 125 ppm of L-carnitine beginning at hatch was the only dietary treatment that sustained a persistent increase in sperm concentration. These results suggest that L-carnitine's antioxidant influence on sperm production begins before the onset of sexual maturity.

Relationships of a transforming growth factor-beta2 single nucleotide polymorphism and messenger ribonucleic acid abundance with bone and production traits in chickens.

Osteoporosis is a serious problem for the laying hen industry with economic, production, and welfare consequences. Transforming growth factor-beta2 (TGFbeta2) has been implicated as an important factor in coupling bone resorption and formation in bone remodeling. The current study was designed to determine if TGFbeta2 was associated with variation in bone mineralization in chickens, using 2 complementary experimental approaches. First, an intronic single nucleotide polymorphism (SNP) present in TGFbeta2 was investigated in an F(2) population to determine its association with bone, growth, and egg traits of importance to the layer and broiler industries. The TGFbeta2 SNP was significantly associated (P < 0.05) with bone mineral density and content. However, these associations became nonsignificant when BW was included as a covariate in analyses. The TGFbeta2 SNP was also significantly associated (P < 0.05) with BW from 1 to 6 wk of age and egg production from 46 to 55 wk of age. To further explore the relationship between TGFbeta2 and bone strength, bone marrow TGFbeta2 mRNA abundance was compared between broiler and layer chickens at 15, 35, and 60 wk of age. Bone and egg traits were measured along with mRNA abundance at each age and found to differ significantly between lines. The TGFbeta2 mRNA abundance was approximately 4-fold greater in broiler compared with layer hens at 15 wk of age but was similar between lines at later ages. Thus, even though the TGFbeta2 SNP will likely not be an effective marker for improving bone strength independently of changes in BW, further research is warranted to investigate the relationship of TGFbeta2 mRNA abundance to bone strength in laying hens.

The effect of dietary ascorbic acid on semen traits and testis histology of male turkey breeders.

A 9-mo field trial was conducted to evaluate the effects of dietary L-ascorbic acid (AA) on semen traits of 144 male turkey breeders. Dietary AA treatments were initiated when birds were 30 wk of age. Semen and blood collection began at 32 wk of age. Three treatments with four pens per treatment and 12 birds per pen were fed 0, 75, and 150 mg/kg AA during the first 4 mo of their reproductive cycle. Levels of AA were doubled in the supplemented diets to 150 and 300 mg/kg during Months 5 to 9. Semen traits and blood AA were unaffected by dietary AA. When birds were 65 wk of age, testes were removed from 12 birds per treatment for histological analysis. Multinucleated giant cells (MCG), indicative of degeneration, were observed in the testes of 7 of the 12 control birds but were absent from AA-supplemented birds (P < 0.02). The antioxidant properties of AA may delay formation of these degenerative cells. In conclusion, dietary AA levels employed in the current study did not affect semen traits or testis weight but were associated with reduced formation of MGC in the testes of 65 wk-old breeder toms.

Ascorbic acid supplementation improved antibody response to infectious bursal disease vaccination in chickens.

The purpose of the present study was to determine if supplementation of ascorbic acid (AA) to the diet would have a beneficial effect on infectious bursal disease (IBD) vaccination of chickens for protection against infectious bursal disease virus (IBDV) infection. Two hundred forty specific pathogen-free (SPF) chickens were divided into eight experimental groups. A 2 x 2 x 2 factorial arrangement in a completely randomized design was used; AA supplementation at 1,000 ppm in the diet, vaccination, and challenge were the main effects. Prior to challenge and 10 d after challenge, serum AA concentration, serum corticosterone concentration, ELISA antibody titer to IBDV, body weight, bursa-to-body weight (B:B) ratio, and bursal histological score (BHS) were determined. Nonvaccinated chickens fed a diet supplemented with AA did not exhibit clinical signs or mortality following challenge, whereas AA-unsupplemented counterparts had 100% cumulative morbidity and 30% cumulative mortality. Serum AA levels of AA-supplemented and vaccinated chickens were significantly (P < 0.05) higher than AA-unsupplemented and vaccinated chickens. Fourteen days following vaccination, significantly (P < 0.05) higher ELISA titers to IBDV were observed in vaccinated chickens supplemented with AA as compared to AA-unsupplemented counterparts. Ascorbic acid-supplemented chickens, especially those also vaccinated, had higher body weight gains as compared to the AA-unsupplemented chickens. Ascorbic acid-supplemented chickens challenged with IBDV did not show any clinical signs or mortality. The results suggest that supplementation of AA at 1,000 ppm in the diet has beneficial effects on antibody response to IBD vaccination and body weight gain.

Phosphorus phase feeding and uterine and isthmus mucosal enzymes and minerals in relation to soft-shelled and shell-less egg production.

The relationships among phosphorus phase feeding, egg shell quality, and the activities and concentrations of several enzymes and minerals in the uterine and isthmus mucosae of hens at the time of oviposition were investigated. During the first 8 months of production (Phase 1), layer diets contained .3, .5, or .7% available phosphorus. Between 9 and 12 months of production (Phase 2), dietary available phosphorus was either increased or decreased by .2% phosphorus, or was left unchanged. No significant differences due to Phase 1 diets were demonstrated for hard-shelled (HS), soft-shelled (SS), or shell-less (SL) egg production, livability, egg weight, or specific gravity. Phase 2 diets had no significant effect on SS or SL egg production, livability, or egg specific gravity; however, decreasing dietary phosphorus reduced egg weight. Levels as high as .9% had no effect on specific gravity or HS egg production, while .1% dietary phosphorus was detrimental to HS egg production and feed consumption. No significant differences due to dietary available phosphorus or egg type (SS vs. HS) were demonstrated for uterine or isthmus mucosal enzyme activities or mineral contents, with one exception. Higher inorganic phosphorus concentrations were found in the uterus of HS egg layers when compared to levels in the uterus of SS egg layers and the isthmus of HS and SS egg layers. Acid phosphatase and carbonic anhydrase activities, and total calcium levels were significantly higher in the isthmus than the uterus, while alkaline phosphatase and pyrophosphatase activities, and inorganic phosphorus levels were significantly higher in the uterus than the isthmus.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of methionine sources for broiler chickens fed corn-soybean meal diets under simulated commercial grow-out conditions.

Two experiments, involving 5,760 birds each, were conducted under simulated commercial grow-out conditions to determine the relative response of broiler chicks to two supplemental levels each of DL-methionine (DL-MET), L-methionine (L-MET), and methionine hydroxy analogue-free acid (MHA-FA) fed on an equimolar basis in corn-soybean meal diets. MHA-FA was shown to support 49-day weight gains comparable to those of chicks fed DL-MET, and both sources were superior to L-MET in this regard. However, there were no significant differences due to MET sources in the efficiency of feed utilization. When compared to basal-fed chicks, birds fed supplemental L-MET, DL-MET, or MHA-FA had elevated plasma free MET levels, whereas cyst(e)ine and taurine concentrations were not affected by dietary treatment. There were no effects of diet on either mortality or the incidence of leg abnormalities. The results of these studies suggest that MHA-FA is an acceptable source of MET for broiler chicks fed corn-soybean meal diets from day-old to market weight.

The relationship of dietary levels of phosphorus to the production of soft-shelled and shell-less eggs.

The relationship among available levels of dietary phosphorus (.2, .3, and .4%) and the production of soft-shelled (SS) and shell-less (SL) eggs was investigated in 864 White Leghorns of a commercial strain. An 11-month performance profile included hen-day production of hard-shelled (HS), SS, and SL eggs, feed consumption, livability, egg weight, and specific gravity. Percent HS egg production and feed consumption were significantly lower and egg specific gravity was significantly higher among hens consuming the .2% available phosphorus diet when compared to hens consuming the .3 or .4% available phosphorus diets. The level of available phosphorus in this study did not affect significantly hen livability or the production of SS or SL eggs. Five hours (HS egg in uterus) or 15 hr (SL egg in uterus) prior to expected oviposition time, 1 ml of a 200 mM phosphate solution was injected into the brachial vein (i.v.) or the uterus (i.u.) of hens observed to lay consistently HS eggs. Injections i.v. did not alter expected oviposition time when either a HS or SL egg was in the uterus, but i.u. injections induced premature oviposition when a SL egg was in utero. The concentrations of inorganic phosphorus and total calcium in the plasma and uterine fluid of hens that laid a high or low incidence of SS + SL eggs were determined 5 hr after the egg entered the uterus. Uterine fluid inorganic phosphorus and total calcium and plasma inorganic phosphorus levels of the high and low incidence groups were not significantly different. However, plasma total calcium was significantly higher among high incidence SS + SL layers when compared to low incidence SS + SL layers at this time during the ovulatory cycle.