Effects of breeder hen age and dietary fat on embryonic and neonatal broiler serum lipids and glucose

Synergy Between Dietary Quercetin and Vitamin E Supplementation in Aged Hen’s Diet Improves Hatching Traits, Embryo Quality, and Antioxidant Capacity of Chicks Hatched From Eggs Subjected to Prolonged Storage

The current study aims to investigate the effects of the synergy between quercetin and vitamin E in aged hen’s diet on hatchability and antioxidant levels of the embryo and newly hatched chicks from prolonged storage eggs. A total of 400 breeder laying hens of 65 weeks of age were selected and randomly divided into 4 groups. Birds were fed a basal diet alone (Control), and basal diets supplemented with quercetin (Q) (0.4 g/kg) and vitamin E (VE) (0.2 g/kg) alone and their combination (0.4 g/kg Q + 0.2 g/kg VE) for 14 weeks, respectively, to determine their effects on yolk antioxidant status, fertility, embryonic mortality, hatchability, antioxidant status of embryonic tissues, as well as the antioxidant status of the newly hatched chicks. The results showed that the hen’s dietary Q + VE increased the yolk weight, as well as increased the antioxidant status of the egg yolk (p < 0.05). Compared with the control group, the supplementation of Q + VE significantly increased the hatchability of set-fertile eggs and decreased early embryonic mortality in eggs stored for 7 and 14 days, respectively (p < 0.05), and also improved the antioxidant capacity of the embryos obtained from eggs stored for 14 days (before incubation) (p < 0.05). Moreover, Q + VE increased the levels of SOD, GSH-Px, T-AOC, T-SOD, and CAT in the liver, heart, and pectoral muscle of the embryo, 1-day-old and 14-day-old chicks (p < 0.05), as well as upregulated the antioxidant related genes (GPx-1, GPx-2, GPx-4, DIO-1, and SOD-1) in the liver of the embryo, 1-day-old and 14-day-old chicks hatched from 14-days storage eggs (p < 0.05). Meanwhile, the MDA levels were decreased by the Q + VE in the embryo and post-hatched chicks (p < 0.05). In conclusion, these findings suggested that maternal dietary Q + VE exerts beneficial synergistic effects on the antioxidant capacity of the egg yolk, embryo, and chicks during prolong egg storage, therefore, Q + VE could be used as a dietary measure to enhance hatchability and chick quality in poultry production.

Exogenous Linoleic Acid Intervention Alters Hepatic Glucose Metabolism in an Avian Embryo Model

In the present study, developmental changes of gluconeogenesis and glycolysis in an avian model were measured, and then the intervention effects of in ovo feeding (IOF) linoleic acid (LA) on hepatic glucose metabolism were evaluated. In Experiment 1, thirty fertilized eggs were sampled on embryonic days (E) of 16, 19, 22, 25, 28, 31, and thirty newly-hatched ducklings at hatch (E34 and E35). In Experiment 2, a total of 120 fertilized eggs (60 eggs for each group) were injected into the yolk sac with PBS as the control group and LA as the IOF LA group on E25. Twelve eggs were selected for sample collection on E28 and E31. Serum contents of glucose, pyruvate, and lactate increased ( p < 0.05) linearly or quadratically from E16 to hatch, as well as hepatic glycogen and pyruvate contents. Hepatic mRNA expression related to energy homeostasis, gluconeogenesis, and glycolysis increased ( p < 0.05) in embryogenesis, and the plateau period was presented on E25–E31. IOF LA decreased ( p < 0.05) serum contents of glucose, triacylglycerol, cholesterol, and hepatic oleic acid, unsaturated fatty acids on E28, as well as the gene expression relative to gluconeogenesis. IOF LA increased ( p < 0.05) pyruvate content in serum and liver, and hepatic gene expression relative to glycolysis on E31. In summary, hepatic gluconeogenesis and glycolysis were enhanced to meet the increasing energy demands of embryonic development during E25 – hatch. Exogenous LA intervention on E25 could inhibit hepatic gluconeogenesis and enhance glycolysis during the later developmental period, disrupting glucose embryonic homeostasis and energy status.

Effects of Sampling and Storage Method on Chicken Blood Glucose Measurement

Glucose is a major circulating carbohydrate in birds and its level in the blood is often used as a biometric indicator in clinical diagnosis and various studies. Notably, hypoglycemia is often associated with Spiking Mortality Syndrome in broilers; therefore, blood glucose levels need to be correctly evaluated in clinical diagnosis. In the present study, we investigated the effect of different blood treatment methods after blood collection on chicken blood glucose measurements. The blood glucose level of plasma separated from blood cell components immediately after blood collection was used as a reference and compared with glucose levels in serum and stored plasma. The mean glucose level in plasma separated from blood cell components immediately after blood collection was 236.1±15.9 mg/dL and remained stable for at least one week in refrigerated storage (between 2°C and 5°C). However, glucose levels decreased slowly in plasma unseparated from blood cell components in storage with ice water. Mean glucose level in serum separated from blood cell components 1 h after blood collection was 206.4±9.2 mg/dL and fell to 108.3±30.0 mg/dL after 24 h. Therefore, the chicken blood serum glucose level was significantly lower than the level in plasma immediately after blood collection, regardless of elapsed time after blood collection. For the measurement of glucose in chicken blood, it is necessary to use refrigeration, use plasma from which blood cell components have been removed, and take measurements within at least 30 min.

Impact of transportation duration on stress responses in day-old chicks from young and old breeders

The aim of this study was to assess the interaction effect of transportation duration and parental age on physiological stress responses and quality in day-old chicks. After hatch, 3240 chicks from either 29-week old (young) or 60-week old (old) broiler breeders were transported for 1.5h (short) or 11h (long). Thereafter, 228 chicks were assessed for quality and blood plasma was assayed for corticosterone (CORT), lactate, glucose, and thiobarbituric acid-reactive substances (TBARS, increased concentrations can indicate oxidative stress). No interaction effects of parental age and transportation duration were found (all P>0.10). Chicks from young breeders showed higher CORT levels (P=0.007) and were of higher quality (Tona method, P<0.001) than those from old breeders. After long transportation, chicks showed increased CORT (P<0.001) and lower TBARS levels (P<0.001) compared to after short transportation. No evidence was provided that long transportation differently affected the quality or stress responses of chicks from breeder flocks of two ages.

Effects of maternal dietary EPA and DHA supplementation and breeder age on embryonic and post-hatch performance of broiler offspring: age and n-3 pufa affect embryonic and post-hatch performance

Breeder age and nutrition are amongst the most important factors affecting progeny growth and development. The present experiment was carried out to evaluate the effects of n-3 fatty acid (FA), with special emphasis on the ratio of eicosapentaenoic (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3) acid, provided to the diet of ageing broiler breeder hens at different ratios, on the incubation parameters and the performance of the offspring. Four hundred and eighty Ross-308 broiler breeder hens were fed one of four different diets (120/treatment), with an equal fat content. The control diet was a basal diet, rich in n-6 FAs (CON). Blends of fish oil were used to enrich the three other diets in n-3 FA and to obtain different EPA/DHA ratios of 1/1 (EPA=DHA), 1/2 (DHA) or 2/1 (EPA). Every 5 weeks, incubation parameters were assessed. Every 15 weeks, offspring was reared until slaughter age on a standard diet. Breeder age affected almost all incubation and post-hatch parameters, whereas n-3 FA treatment only lowered egg weight (p < 0.0001) and consequently hatched chick weight (p < 0.0001). Supplementation of EPA resulted in a higher proportional liver weight (p = 0.0219) at hatch, a lower body weight up to 28 days post-hatch (p = 0.0418), a lower daily weight gain (p = 0.0498) and a higher feed conversion ratio (p = 0.0395) during the starter period (p = 0.0498), resulting in a higher overall offspring feed conversion ratio (p = 0.0317) compared to the control diet. DHA supplementation, on the other hand, resulted in a lower residual yolk weight (p = 0.0220) and a higher overall offspring mortality (p = 0.0125). In conclusion, supplementation of n-3 FA could not counter the adverse effect of breeder flock age, but did not harm incubation or improve post-hatch performance, either. EPA and DHA affected offspring development differently during early post-hatch life.

Effects of different vaccine combinations against Mycoplasma gallisepticum on blood characteristics in commercial layer chickens

Mycoplasma gallisepticum (MG) is a major and economically significant pathogen of avian species. When administered before lay, F-strain MG (FMG) can reduce egg production during lay, but the ts-11 strain of MG (ts11MG) does not exert this effect. Two trials were conducted to determine the effects of pre-lay vaccinations of ts11MG, MG-Bacterin (MGBac), or their combination, in conjunction with an FMG challenge overlay after peak production on the blood characteristics of commercial layers. In each trial, 160 mycoplasma-free Hy-Line W-36 layers were housed in negative-pressure biological isolation units (4 units per treatment, 10 birds per unit) from 9 through 52 wk of age (woa). The following vaccination treatments were administered at 10 woa: 1) Control (no vaccinations); 2) MGBac; 3) ts11MG; and 4) ts11MG and MGBac combination (ts11MG+MGBac). At 45 woa, half of the birds were challenged with a laboratory stock of high-passage FMG. Parameters measured in both trials were whole-blood hematocrit and serum concentrations of cholesterol (SCHOL), triglycerides, calcium, and total protein (STP). An age×treatment interaction (P=0.04) was observed for STP between 23 and 43 woa. The STP concentration in the ts11MG and ts11MG+MGBac groups was higher at 33 woa, but was lower at 43 woa, in comparison to the Control group. Also, at 38 woa, the STP of the ts11MG+MGBac group was higher than that of the MGBac group. Although use of the ts11MG vaccine alone or in combination with MGBac may influence circulating STP concentrations when administered before lay, it remains effective in protecting layers against the adverse effect of a post-peak challenge of FMG on egg production, as was observed in a previous companion study.

Effect of manipulation of incubation temperature on fatty acid profiles and antioxidant enzyme activities in meat-type chicken embryos

Eggs (n = 1,800) obtained from Ross broiler breeders at 32 and 48 wk of age were incubated at either a constant temperature of 37.6°C throughout (T1), or the temperature was reduced for 6 h to 36.6°C each day during embryonic age (EA) 10 to 18 (T2). Yolk sac, liver, and brain fatty acid profiles and oxidant and antioxidant status of liver and brain were measured at EA 14, 19, and day of hatch (DOH). Fatty acid profiles of yolk sac, liver, and brain were influenced by age of breeder with significant breeder hen age × incubation temperature interactions. At EA 14, higher levels of 20:4n-6 and 22:6n-3 had been transferred from the yolk sac to T2 embryos from younger than older breeders, whereas for T1 and T2 embryos, yolk sac 20:4n-6 and 22.6n-3 values were similar for older breeders. Accumulation of 20:4n-6 and 22:6n-3 fatty acids in the liver of T1 and T2 embryos from younger breeders was similar; however, T2 embryos from older breeders had higher liver levels of 20:4n-6 and 22:6n-3 than T1 embryos. At EA 19, liver nitric oxide levels were higher for T2 embryos from younger breeders than those from breeders incubated at T1. Brain catalase levels of T2 embryos from younger breeders were higher than those from older breeders at DOH. Thus, changes in fatty acid profiles and catalase and nitric oxide production of brain and liver tissues resulting from 1°C lower incubation temperature from EA 10 to 18 reflect adaptive changes.

Effects of nicarbazin on the blood glucose and liver glycogen statuses of male broilers

Nicarbazin (NCZ), an effective anticoccidial widely used by the global broiler industry, is known to produce some side effects in broilers. Recent field observations have suggested that NCZ could be associated with spiking mortality syndrome, a disease of uncertain etiology that is most commonly characterized by hypoglycemia. In turn, 2 trials were conducted to investigate the effects of NCZ on the blood glucose levels and liver glycogen content of Ross × Ross 708 male broilers. In 6 of 12 pens beginning at 1 d of age, NCZ was added to basal broiler diets at a rate of 125 mg/kg, and the other 6 pens were control pens in which birds received salinomycin instead of NCZ, at a rate of 66 mg/kg. Feed and water were provided ad libitum, feed was closely monitored in all pens to avoid shortages, no coccidial challenge was imposed, and room temperature never exceeded 29.4°C. At the end of the second trial, a photoperiod increase from 8L:16D to 24L:0D was imposed in an effort to induce stress due to feed engorgement. In response to NCZ in trial 1, 0 to 28 d feed conversion and relative liver weights on d 21 and 28 were higher, whereas 0 to 28 d cumulative BW gain was lower. In response to NCZ in trial 2, 0 to 13 d feed conversion was higher, whereas 0 to 13 d cumulative BW gain was lower. The added NCZ increased blood glucose on d 13 in trial 2, but did not affect at any time the liver constituents analyzed in both trials. In conclusion, the uninterrupted feeding of NCZ at 125 mg/kg in the starter and grower diets of male Ross × Ross 708 broilers increased feed conversion and reduced BW gain, but despite an increase in relative liver weight on d 21 and 28 posthatch, liver glucose and glycogen concentrations were not affected.

Gluconeogenesis differs in developing chick embryos derived from small compared with typical size broiler breeder eggs

We hypothesized that, as the supply of preformed glucose diminishes during development, the embryo would transition to a greater rate of gluconeogenesis (GNG) and that GNG would be greater in embryos from small vs. typical size eggs. Gluconeogenesis by embryos from small (51.1 +/- 3.46 g) and typical size (65 +/- 4.35 g) broiler breeder eggs was measured by dosing [(13)C(6)]glucose (15 mgxegg(-1)) into the chorio-allantoic fluid for 3 consecutive days to achieve isotopic steady-state before blood collection on embryonic day (e) 12, e14, e16, and e18 (4 to 5 eggsxsize(-1)xd(-1)). The (13)C-Mass isotopomer enrichment of blood glucose was determined by gas chromatography-mass spectrometry. On e14, e16, and e18, but not on e12, embryos from small eggs weighed less (P < 0.05) than typical size eggs. For both sizes of eggs, blood glucose concentration, glucose entry rate (g.d(-1)), and Cori cycling and glucose (13)C-recycling (% of entry rate) increased (P < 0.05) with development. On e12 and e14, rates of glucose entry and Cori cycle flux were greater (P < 0.05) for embryos from small eggs. When standardized to BW (g.100 g of BW(-1)xd(-1)), glucose entry and Cori and non-Cori cycle fluxes were greater for embryos from small eggs. From e12 through e18, blood concentrations of gluconeogenic AA (threonine, glutamine, arginine, proline, isoleucine, and valine) were 25 to 48% less (P < 0.01) in embryos from small eggs. In conclusion, embryos from small eggs exhibit greater rates of GNG earlier in development compared with typical size eggs and, perhaps as a consequence, their reduced embryonic growth may result from diverting greater supplies of AA toward GNG.

Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on blood characteristics of commercial laying hens

Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in combination with subsequent time-specific F-strain M. gallisepticum (FMG) inoculations on the blood characteristics of commercial laying hens. The following 4 treatments were utilized: 1) sham vaccination at 10 wk of age, 2) vaccination of ts-11MG at 10 wk, 3) ts-11MG at 10 wk overlaid by FMG inoculation at 22 wk, and 4) ts-11MG at 10 wk overlaid by FMG at 45 wk. Parameters measured in both trials were whole blood hematocrit, plasma protein, serum cholesterol, serum triglycerides, and serum calcium. No significant age x treatment interactions and no significant age or treatment main effects were observed for any of the blood parameters investigated, except for serum calcium. At wk 22, serum calcium concentrations were increased by vaccination with ts-11MG at 10 wk, and levels were further increased when the ts-11MG vaccination at 10 wk was overlaid by an FMG inoculation at 22 wk. These results suggest that ts-11MG vaccination at 10 wk of age alone or combined with F-strain inoculum overlays at either 22 or 45 wk may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers. Because elevations in serum calcium were not associated with changes in hen performance, as reported in a previous companion article, it is further suggested that prelay ts-11MG vaccination before FMG inoculation overlays during lay may provide adequate protection against field strain M. gallisepticum infections while being innocuous to layer performance.

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.

Egg quality and yolk polyunsaturated fatty acid status in relation to broiler breeder hen age and dietary n-3 oils

The effects of broiler breeder hen age and dietary n-3 oils on yolk n-3 and n-6 fatty acid composition, egg quality, fertility, and hatchability were investigated. A total of 2,200 eggs were collected from wk 26 through 62 from Cobb breeder hens fed diets containing 1.75% fish oil + 1.75% yellow grease (low n-3) or 3.5% fish oil (high n-3). Eggs obtained from a commercial source were used as the control for n-6 and n-3 fatty acid composition and hatchability studies. A significant decrease in egg weight, yolk weight, shell weight, and yolk color was observed for high n-3 when compared with low n-3 eggs (P < 0.05). No difference was noted in egg total fat content due to dietary treatments. However, egg fat was highest at 42 wk for high and low n-3 eggs when compared with other weeks (P < 0.05). Total n-3 fatty acids, docosahexaenoic acid (DHA, 22:6 n-3), and the DHA:arachidonic acid (AA, 20:4 n-6) ratios were higher in high n-3 eggs when compared with low n-3 eggs. The incorporation of DHA was lowest at wk 26 and highest at wk 38 for low and high n-3 eggs (P < 0.05). Low n-3 and high n-3 eggs at the oldest age had the highest level of AA (P < 0.05). A positive correlation between hen age and egg yolk AA content was observed. The r(2) values for AA in low n-3 and high n-3 eggs were 0.91 and 0.90, respectively (P < 0.05). The total content of long-chain (>18-C) n-6 PUFA (AA+ 22:4 n-6+22:5 n-6) constituted over 0.3 g per commercial egg when compared with 0.09 and 0.07 g in low and high n-3 eggs, respectively. The content of DHA in commercial eggs was negligible (<0.5%) when compared with low and high n-3 (P < 0.05). The overall fertility was 98.6 and 97.4%, and hatchability of fertile eggs was 80 and 83.8% for low and high n-3 eggs, respectively (P > 0.05). The overall fertility was 96%, and hatchability of fertile eggs was 80% for commercial eggs.

Effects of supplemental dietary phytase and 25-hydroxycholecalciferol on the blood characteristics of commercial layers inoculated before or at the onset of lay with the F-strain of Mycoplasma gallisepticum

In 3 trials, the effects of dietary supplementation with phytase (PHY) and 25-hydroxycholecalciferol on BW and the blood characteristics of commercial layers that were inoculated prelay (12 wk of age) or at the onset of lay (22 wk of age) with F-strain Mycoplasma gallisepticum were assessed at 34, 50, and 58 wk of age. Experimental layer diets, which included either a basal control diet or the same diet supplemented with 0.025% PHY and 25-hydroxycholecalciferol, were fed from 20 through 58 wk of age. The supplemented diet decreased blood hematocrit values across bird age, inoculation type (sham vs. F-strain M. gallisepticum), and age of inoculation (prelay vs. onset of lay). Phytase- and 25-hydroxycholecalciferol-supplemented diets reduced bird BW in sham-inoculated control birds across bird age and age of inoculation. This effect was not observed in F-strain M. gallisepticum-inoculated birds. Furthermore, across diet (control vs. supplemented) and inoculation type, total plasma protein concentration at 34 wk of age was higher in birds that were inoculated at the onset of lay compared with those inoculated prelay. Diet, inoculation type, and inoculation age had no effect on mortality, reproductive organ histopathological lesion scores, or serum cholesterol and Ca concentrations. In conclusion, throughout lay, the supplementation of commercial layer diets with PHY may lower hematocrit, and inoculation with F-strain M. gallisepticum prelay or at the onset of lay may ameliorate the depressing effects of dietary PHY and 25-hydroxycholecalciferol supplementation on hen BW.

Nutrition of the developing embryo and hatchling

Nutrient needs central to satisfactory egg incubation well-being undergo several major changes from fertilization until the reliance of the chick on feed. Glucose is central, with the initiation of incubation until the chorioallantois accesses O(2) to use for fatty acid oxidation. Nutrient recovery from albumen and yolk is largely commensurate with body assembly through to completion of the embryo by 14 d. Remaining albumen mixes with the amniotic fluid and is orally consumed until initiation of emergence. A portion of the albumen is absorbed by the small intestine to expand body glycogen reserves. The residual not absorbed contains digestive enzyme contributions and enters the yolk sac through its stalk at the jejunum and ileum. Interaction of the albumen-amnion digestive enzyme mixture with yolk sac contents leads to diverse alterations that influence subsequent use of lipids. Rapid removal of very low-density lipoprotein ensues, until pipping with triglycerides, expanding body fat depots while cholesterol deposits in the liver. A concurrent translocation of Ca from shell mineralizes the skeletal system while also crossing yolk sac villi for deposition on phosvitin-based granules accruing in its lumen. Loss of chorioallantois with pipping and the start of pulmonary respiration predispose a dependence on glycolysis to support emergence. Small intestinal villi progressively reorient their enterocytes from macromolecule transfer to competence at digestion and absorption after hatching. Mobilization of body fat complements contributions from the yolk sac to provide fatty acids for generating energy, heat, and water while also combining with hepatic cholesterol for membrane expansion and continued development. Calcified granules evacuate the yolk sac to further skeletal mineralization in the absence of shell contributions. Egg mass, its interior quality, and turning during early incubation directly influence the ability of the embryo to access nutrients and provide resources to support emergence and the transition of the chick to self-sufficiency.

Effects of S6-strain Mycoplasma gallisepticum inoculation at ten, twenty-two, or forty-five weeks of age on the blood characteristics of commercial egg-laying hens

In 2 consecutive trials of the current study, the effect of the age of application of S6-strain Mycoplasma gallisepticum (S6MG) inoculation on the blood characteristics of commercial layers housed and maintained under controlled conditions was determined. The ages of inoculation compared were those before lay at 10 wk of age, during onset of lay at 22 wk of age, and during postpeak lay at 45 wk of age. In each trial, hematocrit, plasma protein, and serum cholesterol, triglycerides, and Ca were determined at 20, 24, 32, 43, 47, and 58 wk of age. The data from both trials were pooled then analyzed together, whereas, data from wk 20 (effect of 10-wk S6MG inoculation); data from wk 24, 32, and 43 (effects of 10- and 22-wk S6MG inoculations); and data from wk 47 and 58 (effects of 10-, 22-, and 45-wk S6MG inoculations) were analyzed separately. At wk 20, hematocrit was higher in birds inoculated with S6MG at 10 wk compared with sham-inoculated birds, and across wk 24, 32, and 43, serum Ca was higher in birds inoculated with S6MG at 10 or 22 wk compared with those that were sham-inoculated. Serum Ca level across wk 47 and 58 was higher in birds inoculated with S6MG at 10 wk compared with sham-inoculated controls and birds inoculated with S6MG at 22 wk, with 45-wk S6MG-inoculated birds being intermediate. The response of serum cholesterol level at 47 wk to S6MG inoculation at either 10, 22, or 45 wk compared with controls was nearly opposite to that of the response observed at 58 wk. However, serum triglycerides were depressed only at wk 47 due to the 45-wk S6MG inoculation compared with all other treatments. Variable post-peak alterations in serum Ca and lipids occur in response to the timing of S6MG inoculation in layers housed under controlled conditions.

Relationships among prehatch and posthatch physiological parameters in early nutrient restricted broilers hatched from eggs laid by young breeder hens

The objective of this study was to establish relationships among various physiological parameters in early (through 72 h posthatch) nutrient restricted broiler chicks from young breeder hens. Despite a 19% decrease in mean BW between 0 and 72 h posthatch, there were no chick mortalities. Liver glycogen peaked at 24 h, and peaks in rectal temperature, plasma glucose, and plasma refractive index occurred at 48 h. By 24 h, negative correlations were noted between BW and relative liver weight and between liver glycogen and both refractive index and rectal temperature. By 24 h, positive correlations were noted between relative liver weight and liver glycogen, BW and plasma glucose, rectal temperature and plasma glucose, and rectal temperature and body fat loss score. Mean daily relative egg weight loss between 0 and 19 d of incubation (RIEWL) was positively correlated with rectal temperature at 0 h but was negatively correlated with rectal temperature at 24 h and liver glycogen at 24 and 48 h. Furthermore, mean relative hatching chick weight (RHCW) had significantly positive correlations with plasma glucose at 6 h and rectal temperature at 48 and 72 h. Broilers having a greater RHCW after hatching from eggs with a lower RIEWL may maintain higher metabolic rates between 24 and 72 h posthatch despite nutrient deprivation. However, broiler chicks from eggs exhibiting a higher than optimal RIEWL may have greater dependence on gluconeogenesis, thus requiring stricter management during initial brooding.

Effects of fasting on serum lipids and lipoprotein profiles in the egg-laying hen (Gallus domesticus)

The effects of a 24-h fast on serum lipids and lipoprotein profiles in commercial laying hens were investigated. Blood was analyzed at 34 and 46 weeks of age from Single Comb White Leghorn hens that had been either fed ad libitum or had been fasted for 24 h prior to collection. At 12 weeks, birds were divided into 16 biological isolation units, with 8 replicate units assigned to each treatment group. Four birds out of 10 in each unit were tagged for bleeding. Parameters evaluated included total serum cholesterol and triglycerides, mean diameters of very low density lipoproteins (VLDLs) for the 10th, 50th, and 90th percentiles of serum total VLDL, mean total population VLDL particle diameter (MPD), and percentage serum cholesterol recovered in VLDL, low density lipoprotein (LDL), and high density lipoprotein (HDL) fractions. Fasting led to decreases in total serum cholesterol and triglycerides, and a decrease in mean serum VLDL particle diameter in the 90th population percentile. At Week 34, percentage serum cholesterol recovered from LDL was increased, whereas percentage serum cholesterol recovered from HDL was decreased due to fasting. At Week 46, MPD and percentage serum cholesterol recovered from VLDL were decreased, whereas percentage serum cholesterol recovered from HDL was increased due to fasting. It was concluded that a 24-h fast decreased serum lipids (cholesterol and triglycerides) and the size of VLDL particles in the 90th population percentile in commercial laying hens. Furthermore, bird age influenced the effects of a 24-h fast on MPD and the redistribution of serum cholesterol among VLDL, LDL, and HDL particles.

Post-hatching dynamics of plasma biochemistry in free-living European starlings (Sturnus vulgaris)

This is the first study of plasma biochemical parameters in free-living altricial birds during an entire developmental period in a nest, represented by European starling (Sturnus vulgaris). Dynamics of postnatal changes from hatching until close to fledging (days 1 to 15) were registered. Parameters of protein metabolism represented by total proteins, albumin and globulin concentrations increased continuously during the observed developmental period. There were two peaks in uric acid concentration on days 5 and 11. To the contrary, the creatinine content did not change throughout the observed period and increased only on day 15. Creatine kinase activity gradually increased until day 11 and then fell before fledging. Parameters of lipid metabolism (concentration of total lipids, triacylglycerols and nonesterified fatty acids) in plasma increased gradually reaching a plateau between days 8 and 11 and then declined on day 15. The cholesterol concentration pattern was similar to maximum value on day 11, then consecutively decreased. Concentration of glucose increased until day 8 and remained unchanged until fledging. Whereas calcium reached the highest concentration during days 8 and 11, phosphorus peaked earlier on day 5. The activity of alkaline phosphatase was similar to the pattern found in calcium concentration. Presented data showed an increase in both protein and lipid metabolism during the phase of rapid growth. A remarkable decrease in parameters of lipid metabolism before fledging may reflect increased physical activity and changes in nutrition.

Effects of F-strain Mycoplasma gallisepticum inoculation at twelve weeks of age on the blood characteristics of commercial egg laying hens

In two trials, the effects of an F-strain Mycoplasma gallisepticum (FMG) inoculation at 12 wk of age on the blood characteristics of commercial Single Combed White Leghorn laying hens were investigated throughout lay. Variables measured in both trials were whole blood hematocrit, plasma protein (PP), and serum cholesterol, triglycerides (ST), and calcium. In both trials, hematocrit at 20 wk of age was significantly increased in birds inoculated with FMG. In trial 1, ST and PP were significantly increased at 22 wk of age by FMG, while ST and PP were significantly decreased in FMG-inoculated birds at wk 54 and 52, respectively. When combined with the establishment of an FMG infection, the initial weeks of egg production become particularly stressful to the bird. Increases in these independent blood parameters between 8 and 10 wk postchallenge are suggestive of compensatory responses in these birds to an FMG challenge. Postpeak decreases in both ST (54 wk) and PP (52 wk) in FMG-infected birds may be the result of a more chronic effect of FMG on lipid and protein synthesis in the liver. These data are the first to suggest that alterations in egg production in response to FMG-infection in commercial layers, as noted in a previous report, may be associated with changes in hematocrit. However, because ST and PP were not affected by FMG in both trials, the responses of these blood parameters to FMG-infection may be inconsistent among flocks.

Effects of incubator humidity and hen age on yolk composition in broiler hatching eggs from young breeders

The effects of broiler breeder age (26, 28, and 30 wk) and incubator relative humidity (43, 53, and 63% RH) on yolk sac weight and composition in broiler hatching eggs between 16 and 19 d of incubation were evaluated. Percentage yolk sac weight was reduced in eggs from the youngest (26 wk) breeder hens and in eggs incubated at 53% RH. Percentage yolk moisture, in eggs from the youngest hens, was lowest at 16 d and was highest at 19 d, and percentage yolk lipid was highest at 16 and 17 d of incubation in eggs from 30-wk-old hens. Percentage yolk lipid content was higher at 63% RH compared with 53% RH in eggs from 26-wk-old breeders but was lower in eggs incubated at a 43% RH compared with 53 and 63% RH from 30-wk-old breeders. Yolk stearic and arachidonic acid concentrations were higher and myristic acid concentration was lower in eggs from the 26-wk-old hens. Conversely, the highest yolk concentrations of linolenic and palmitoleic acids occurred in eggs from 30- and 28-wk-old breeders, respectively. At 16, 17, 18, and 19 d of incubation, yolk oleic acid concentrations were significantly, but variably, affected by breeder age, whereas linoleic acid concentration was highest in 26-wk-old breeders only at 19 d. Palmitic acid concentration at 17 d was lower in eggs incubated at 53% RH compared with 43 and 63% RH. Rate of yolk uptake from the yolk sac by embryos may be increased by incubating eggs at 53% RH, and the effects of changes in RH between 43 and 63% on yolk lipid content are influenced by breeder age.

Breeder age influences embryogenesis in broiler hatching eggs

The effects of dietary fat and broiler breeder age on egg and embryo characteristics during incubation were investigated. Breeders were fed diets containing no added fat or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen day (pC/d), or 1.5% PF or 3.0% corn oil at 449 pC/d. Feeding of diets was initiated at 22 wk, and eggs were collected for incubation at 27 and 36 wk of age. Percentage incubational egg weight loss was determined between day of set and Days 6, 12, and 18. Percentage wet and dry embryo weights, embryo moisture content, and eggshell weights were determined at 6, 12, and 18 d of incubation. Percentage yolk sac weight and wet and dry liver weights and moisture content were determined on Days 12 and 18. Percentage gall bladder weight was determined on Day 18. There were no observed effects due to breeder diet. However, eggshell weight at Days 6, 12, and 18 was higher in 27-wk-old hens compared with 36-wk-old hens. Conversely, egg weight loss between Day 0 and Days 6, 12, and 18 and yolk sac weight across Days 12 and 18 of incubation were lower in eggs at 27 wk of age compared with 36 wk. At Day 18, dry embryo weight was higher and wet liver weight was lower at 27 wk compared with 36 wk. A slower rate of DM accumulation in embryos at Week 36 compared to Week 27 was associated with increased incubational water loss and decreased embryo moisture content, eggshell percentage, and yolk sac absorption rate. These data demonstrate that changes in eggshell characteristics with broiler breeder age can alone impact yolk uptake, growth, and body composition in subsequent embryos.

Effects of conjugated linoleic acid. 2. Embryonic and neonatal growth and circulating lipids

The present study was designed to investigate the effects of conjugated linoleic acid (CLA) on yolk usage and circulating very low density lipoproteins (VLDL) during incubation (Day 15) and through 6 d post-hatch. Eggs enriched with CLA were obtained from hens subjected to the following treatments. Group A hens served as the control group, Group B hens received 1 g CLA every other day, Group C hens received 1 g CLA every 4th d, and Group D hens were sham-supplemented with 1 g safflower oil every other day. Enrichment with CLA did not effect fertility, hatch of fertile, BW, or yolk-free BW of embryos or chicks. However, there were significant changes in relative yolk sac weight (RYW) and composition of circulating VLDL particles. Across all dietary treatments (Groups B, C, and D), 15-d embryos had smaller RYW compared with Group A embryos; this difference remained through 2 d posthatch. During that period (15 d of incubation through 2 d posthatch), however, embryos and chicks from Group B hens exhibited a unique absorption pattern such that little to no yolk was utilized between hatch and 2 d posthatch, a period normally characterized by high yolk lipid utilization. Similar to the RYW effects, VLDL particles were also altered by hen-induced treatment. Specifically, at hatch, chicks from Group A hens had the highest percentage of triglycerides (TG) within their VLDL particles compared with chicks from hens under all other treatments. This trend in VLDL particles was continued at 4 d posthatch. The present study demonstrates that CLA enrichment of eggs alters relative yolk sac absorption and the composition of circulating VLDL particles.

[The effect of palm oil and safflower oil in the feed of parent fattening hens on fertility, hatchability and growth of progeny]

The aim of two experiments with broiler breeder hens was to evaluate the effect of diets containing palm butter or safflower oil (25 g and 50 g/kg feed, resp.) on fertility, hatchability and growth of progeny. Especially the incorporation of oleic and linoleic acid in egg yolk reflected the dietary fatty acid source. Eggs were collected and stored in the incubator at a hen age of 31, 40, 50, and 60 weeks. Hatched chicks were reared over 5 weeks. The number of fertile eggs (Experiment 1 and 2, 75 and 88%, resp.) differed between the experiments (P < or = 0.05). Neither embryonic mortality nor hatchability (Experiment 1 and 2, 76 and 78%, resp.) were significantly affected by fatty acid composition of yolk. No clear maternal dietary effect was recorded on chicken weight at hatching (Experiment 1 and 2, 43.3 g and 43.7 g, resp.) and at 35 days of age (Experimental 1 and 2, 1676 g and 1764 g, resp.) The fatty acid composition in the analysed egg yolk sac of chicks showed a different fatty level but corresponded to fatty acid composition of breeding eggs before incubation. According to a decreased level of docosahexaenoic acid in egg yolk due to increased incorporation of linoleic acid, the content of this fatty acid was also diminished in phospholipids of the brain of chicken on days 1 and 5 after hatching.

Effects of breeder age and dietary fat source and level on broiler hatching egg characteristics

The effects of breeder age and added dietary fat source and level on broiler hatching egg characteristics were evaluated. Diets included no added fat (NAF) or 3.0% added poultry fat (PF) for peak energy intakes of 430 and 467 kcal/hen-day (PCD) or 1.5% PF or 3.0% corn oil (CO) at 449 PCD. As added dietary fat was changed from CO to PF, the percentage of unsaturated dietary fatty acids, including linoleic acid, decreased. Feeding of experimental diets was initiated when breeders were 22 wk old. Total fresh egg weight; eggshell weight; percentages of yolk (PYK), albumen (PAB), and eggshell (PSHL) weights; and yolk:albumen ratio were measured at various weeks between 26 and 47 wk of age. Egg weight increased progressively with hen age. Significant increases in yolk:albumen ratio occurred between Weeks 26 and 31 and between Weeks 31 and 35. Low (430 PCD) dietary energy levels significantly reduced PYK at 35 wk and increased PAB across breeder age. Eggshell weight was lower in birds fed moderate (449 PCD) compared to low energy levels at Week 26, moderate compared to high (467 PCD) energy levels at Week 41, and PF compared to CO across fat level at Week 31. At Weeks 31 and 41, PSHL was increased by the use of 3.0% PF compared to 1.5%, and PSHL was increased at Weeks 26 and 41 by using added PF compared to CO across fat level. Increased dietary energy decreased PAB and the use of added dietary CO rather than PF decreased PSHL in broiler breeders between 26 and 47 wk of age.

Effects of dietary fat type and level on broiler breeder performance

The effects of added dietary fat type and level on broiler breeder performance were evaluated in two trials. In Trial 1, diets included no added fat (NAF) or 3.0% added poultry fat (PF) for individual bird energy intakes of 430 and 467 kcal/d at peak production (PCD), or 1.5% PF or 3.0% corn oil (CO) at 449 PCD. In Trial 2, diets contained NAF, 1.5 or 3.0% added CO or PF, or 3.0% lard (LA) for peak energy intakes of 463 PCD. All diets in Trial 2 were isocaloric and isonitrogenous. Feeding of experimental diets was initiated when breeders were 22 wk old in both trials, and hen BW was measured at various weeks between 22 and 47 wk in Trial 1 and between 27 and 65 wk in Trial 2. Egg production, egg weight (EW), eggshell quality, and hatchability were recorded at various weeks between 24 and 48 wk in Trial 1 and between 27 and 64 wk in Trial 2. Body weights and EW increased progressively, and eggshell quality fluctuated variably with age. Egg production peaked between Weeks 32 and 35, and hatchability was significantly depressed at Week 63. Egg weight and hatchability were not affected by dietary treatment; however, BW increased with energy level in the diet between Weeks 27 and 47. Body weight was also higher in birds fed 1.5 or 3.0% added fat compared with NAF and was higher in birds fed LA compared with CO at the 3.0% level. Egg specific gravity and shell weight per unit of surface area at Week 41 were increased by feeding low or high energy compared with moderate energy, and relative eggshell conductance was increased by using moderate compared with high energy diets and by feeding 1.5% PF compared with 3.0% PF. Egg specific gravity was increased by PF when compared with CO across fat level at Weeks 26 and 47 and by LA when compared with PF across fat level and breeder age. These data suggest that certain dietary energy and fat regimens may affect BW and eggshell quality without associated effects on EW and hatchability at various breeder ages.

Effects of breeder age and dietary fat on subsequent broiler performance. 1. Growth, mortality, and feed conversion

The effects of breeder age (35, 51, and 63 wk) and added dietary fat on subsequent broiler growth, mortality, and feed conversion through 42 d were evaluated. Beginning at 22 wk of age, diets included 0, 1.5, or 3.0% added poultry fat (PF), 1.5 or 3.0% added corn oil (CO), or 3.0% added lard (LA). Broilers from hens 35 wk of age performed better between 0 and 21 d than those from 51- and 63-wk-old hens. Conversely, between 22 and 42 d, broilers from hens 51 wk of age performed better than those at 35 and 63 wk. In relation to PF, CO added to breeder diets increased 0 to 21 d BW gain in broilers; whereas, feed conversion between 22 and 42 d was reduced in broilers from hens fed PF compared to those fed CO. In conclusion, breeder age influenced broiler performance differently throughout the growout period. Fat added at the 1.5% level to breeder hen diets was an effective energy source. However, less saturated fat improved growout performance.

Effects of dietary fat and eggshell cuticle removal on egg water loss and embryo growth in broiler hatching eggs

The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.

Broiler breeder age and dietary fat influence the yolk fatty acid profiles of fresh eggs and newly hatched chicks

The purpose of the present study was to investigate the combined effects of breeder age (36-, 51-, or 64-wk) and different dietary fat sources (3% added corn oil, poultry fat, or lard) on lipids in fresh egg yolks and yolks of newly hatched chicks. Isocaloric breeder diets were altered by the inclusion of different types of dietary fat such that the poultry fat and lard diets had the highest levels of saturated fatty acids when compared to the corn oil diet. Fresh egg yolks obtained from 36-wk-old breeders exhibited higher levels of palmitoleic acid when compared to the levels observed in fresh egg yolks of 51- or 64-wk-old breeders. Furthermore, these levels decreased significantly by 21 d of incubation only in eggs from 36-wk-old hens. At 36 wk of breeder age, the levels of oleic and arachidonic acid were higher in yolks from hatched chicks than in previous fresh egg values, regardless of type of added dietary fat; whereas the level of linoleic acid was higher only in yolks from hatched chicks compared to those of fresh eggs from 36-wk-old hens fed 3% added corn oil. These data suggest that breeder age influences the utilization of yolk lipid by developing embryos, and that the type of fat provided in the diet may have an additional influence.

Effects of added lard fed to broiler chickens during the starter phase. 1. Body and selected organ weights, feed conversion, hematology, and serum glucose

The effects of added lard in starter diets on BW, selected organ weights, feed conversion, hematological indices, and serum glucose were determined weekly in broiler chickens between 14 and 42 d of age. Nonisocaloric starter diets were formulated to contain either 0, 3, or 7% added lard, where the megacaloric percentages of all major nutrients were held constant. Broiler chickens received either 0, 3, or 7% added lard in starter diets through 10 d of age (S1), followed by either 3 or 7% added dietary lard through 21 d of age (S2). All possible combinations of the three S1 diets and two S2 diets yielded six total dietary treatments. A common grower diet was provided after 21 d. Body weight was not affected by diet and feed conversion did not increase between 21 and 42 d when birds were fed 3 or 7% added lard in the S1 diet. The effects of the S1 and S2 diets on relative liver weight were inconsistent over time and were not influenced by sex. Hematocrits were increased across time in birds fed 3% S1 diets and plasma protein concentrations were increased at 14 d in birds fed 7% S1 diets. It was concluded that the response of broiler chickens between 14 and 42 d to different levels of dietary lard was influenced by age of feeding during the starter period.

Naloxone attenuates serum corticosterone and augments serum glucose concentrations in broilers stimulated with adrenocorticotropin

The effects of exogenous naloxone and adrenocorticotropin (ACTH) on circulating concentrations of corticosterone and glucose in broilers were determined. Birds were injected i.m. at 0 and 2 h with either saline or naloxone, then i.v. at 2.5 h with either saline or ACTH. Control birds received saline at each injection. Blood samples were taken before the experiment started (0 min) and 30, 60, and 90 min after the last injection. Intramuscular injections of naloxone significantly reduced subsequent ACTH-stimulated increases in serum corticosterone; however, when followed by saline, naloxone elevated corticosterone by 90 min after the final injection of saline. Glucose levels were significantly elevated at 60 min in birds receiving ACTH i.v., but remained elevated through 90 min in birds pretreated with naloxone. Naloxone pretreatment attenuated serum corticosterone but augmented serum glucose concentrations in ACTH-stimulated broilers.

Continuous infusion of adrenocorticotropin elevates circulating lipoprotein cholesterol and corticosterone concentrations in chickens

The purpose of the present study was to investigate the effects of elevated corticosterone (CORT) on circulating lipoprotein cholesterol during a 1-wk period. For this study, 15 commercial broilers were randomly assigned to one of three treatment groups. Group 1 served as the control (CON) and received no treatment, whereas Groups 2 and 3 received subcutaneous mini-osmotic pumps containing either physiological saline (PS) or adrenocorticotropin (ACTH), respectively. The ACTH was delivered at a rate of 8 IU/kg of BW/d. Blood samples were taken at Time 0 (before implants) and on Days 2, 4, and 7 postimplantation. Continuous infusion of ACTH increased plasma glucose, cholesterol, triglycerides, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, and CORT during the postimplantation period. The group treated with ACTH also exhibited a decrease in BW during the last 2 sampling d. There were no differences in any of the serum constituents measured between CON and PS birds, which suggest that CON birds can serve as useful controls. These data suggest that birds given a continuous infusion of ACTH at 8 IU/kg of BW/d can experience changes in plasma lipoprotein cholesterol concentrations along with changes in other blood parameters and may serve as a useful model in accelerated lipoprotein production.