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The aim of this experiment was to investigate the effect of n-3 fatty acid (FA) supplemented diets on breeder performance, productivity and egg quality. Breeders (n = 480) were fed the supplemented diet from 18 weeks onwards; the inclusion level of n-3 FA was increased from 1.5% to 3.0% from 34 weeks of age onwards until 48 weeks of age. Ross-308 broiler breeders (n = 480) were fed one of four different diets: a basal diet rich in n-6 FA (control diet) or one of three diets rich in n-3 FA. For the n-3 FA diets, eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) were fed to the broiler breeders at different ratios formulated to obtain EPA/DHA ratios of 1/1, 1/2 or 2/1. Differences in performance, reproduction and egg quality parameters due to n-3 supplementation were noted more for the 1.5% followed by the 3.0% fed broilers than their 1.5% supplemented counterparts. Egg weight (p < 0.001) and egg mass (p = 0.003) were significantly lower and feed conversion (p = 0.008) significantly higher for the n-3 FA (at 3.0% inclusion level) fed broilers compared to the control group. For the EPA- and DHA-fed breeders, a higher proportional abdominal fat percentage (p = 0.025) and proportional albumen weight (%) (p = 0.041) were found respectively. Dietary treatments did not affect reproduction. It can be concluded that the results of the present experiment indicate no significant differences between treatments at 1.5% inclusion levels. However, increasing this level to 3.0% is not recommended due to the rather negative effects on the measured parameters. It should be further investigated whether these adverse effects were obtained due to (i) the higher supplementation level, (ii) combining a supplementation level of 1.5% with 3% or (iii) the duration of supplementation.

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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.

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To examine the relationship of insulin and glucose, broiler embryos were subjected to acute or prolonged hypoglycemia during the late embryonic phase by, respectively, injecting once (at embryonic day [ED] 16 or 17) or on 3 consecutive days (ED 16, 17, and 18) with tolbutamide (80 µg/g embryo weight), a substance that stimulates insulin secretion from the pancreas. After 1 tolbutamide injection, a prolonged (32 h) decrease of plasma glucose and a profound acute increase in plasma insulin were observed. The 3 consecutive tolbutamide injections induced hypoglycemia for 4 days (from ED 16 to ED 19). The postnatal performance after 3 consecutive tolbutamide injections in broiler embryos was also investigated. Body weight was lower in tolbutamide-treated chickens from hatch to 42 d compared with sham (P = 0.001) and control (P < 0.001) chickens. Feed intake was lower in the tolbutamide group from hatch to 42 d as compared with sham (P = 0.007) and control (P = 0.017) animals. In addition, at 42 d, plasma glucose concentrations, after an insulin injection challenge (50 µg/kg body weight), were higher in tolbutamide-treated chickens compared with the sham and the control group as were their basal glucose levels (P value of group effect <0.001). In conclusion, tolbutamide treatment during the late embryonic development in broilers resulted in prolonged hypoglycemia in this period and negatively influenced the posthatch performance.

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This study investigated whether offspring from n-3-supplemented breeders have an enhanced performance and immune organ weight when fed a post-hatch n-3-enriched diet in comparison with their control-fed counterparts and the importance of timing of omega-3 supplementation. Therefore, 480 Ross-308 broiler breeder hens were fed one of four different diets (120/treatment). The control diet (CON) was a basal diet, rich in n-6 fatty acids (FA). The three other diets were enriched in n-3 FA, formulated to obtain a different EPA/DHA ratio of 1/1 (EPA = DHA), 1/2 (DHA) or 2/1 (EPA). At 33 weeks of age, eggs were incubated to obtain 1440 offspring. They were set up according to their maternal diet and sex in 48 pens of 30 chicks each (12 pens per maternal treatment: six male and six female). Half of the offspring were given a post-hatch control diet, whereas to other half received an n-3-supplemented diet. Zootechnical performance was followed for starter, grower and finisher phase, and at the end of each phase two, chicks per pen were sacrificed to determine the weight of the immune organs. No interaction was found between maternal and post-hatch n-3 treatment for zootechnical performance. An interaction arose between the maternal and post-hatch n-3 supplementation for proportional bursa weight at day 1 and day 14 and proportional liver weight at day 14, but effects on immune organ weight were rather limited. Offspring post-hatch n-3 supplementation did not enhance maternal n-3 supplementation.

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Broilers were injected at 10 days of age with either Escherichia coli lipopolysaccharides (LPS) or with Freund's adjuvants (FA) to investigate its triggering effect on the acute phase reaction (APR). First the kinetics of certain APP was studied by sampling blood 4 h, 8 h, 12 h and 24 h post injection with LPS. Ovotransferrin (OVT) and α-1 acid glycoprotein (AGP) concentration increased with time post injection (PI) with LPS to reach a plateau at 12 and 24 h PI. Caeruloplasmin (CP) did not increase with time PI. Compared to injection with phosphate buffered saline, OVT concentrations were higher when injecting chicks with LPS at all time points PI. At 24 h PI, LPS injection resulted in higher OVT and AGP concentration compared to injection with FA. It is recommended to use LPS instead of FA to trigger the APR. The best time point to sample blood for APP determination is 24 h PI.

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When added to the feed of broiler breeder hens, dietary polyunsaturated fatty acids (FA) can be incorporated into the yolk and therefore become available to the progeny during their early development. The mechanism involved in lipid metabolism and deposition in the egg may be influenced by breeder age. Before the effect of an elevated concentration of certain polyunsaturated FA on the embryo can be investigated, the effect at breeder level and egg quality must be further assessed. The aim of the present experiment was to evaluate the effects of dietary n-6/n-3 ratios and dietary eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) ratios, provided to broiler breeder hens, in terms of their zoo technical performance, egg quality, and yolk FA composition. Starting at 6 wk of age, 640 Ross-308 broiler breeder hens were fed 1 of 4 different diets. The control diet was a basal diet, rich in n-6 FA. The 3 other diets were enriched in n-3 FA, formulated to obtain a different EPA/DHA ratio of 1/1 (EPA = DHA), 1/2 (DHA), or 2/1 (EPA). In fact, after analysis the EPA/DHA ratio was 0.8, 0.4, or 2.1, respectively. Dietary EPA and DHA addition did not affect the performance of the breeder hens, except for egg weight. Egg weight was lower (P < 0.001) for all n-3 treatments. Dietary EPA improved number of eggs laid in the first 2 wk of the production cycle (P = 0.029). The absolute and relative yolk weight of eggs laid by EPA = DHA fed hens was lowest (P = 0.004 and P = 0.025, respectively). The EPA and DHA concentrations in the yolk were highly dependent on dietary EPA and DHA concentrations with a regression coefficient equal to 0.89. It can be concluded that dietary EPA and DHA can be incorporated in the breeder egg yolk to become available for the developing embryo, without compromising the performance and egg quality of the flock.

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It is not rare that newly hatched chicks remain without feed for about 24 to 48 h before they are placed on farms due to a series of logistic operations. Furthermore, the spread in hatching time can also mount up to 30 to 48 h for late v. early hatchers. In other words, the practice is a complex combination of spread of hatch and delayed feed access. The present study was aimed to investigate the combined effects of hatching time with a delay in feed access of 48 h, starting from their hatch-time (biological age). When chicks had access to feed immediately after hatch, late hatchers had a higher feed intake and relative growth rate up to day 5 compared with their early hatched counterparts. Feed deprivation during the first 48 h resulted in retarded early growth rate, which was further aggravated by an impaired feed intake after refeeding. In addition, the differential effects of hatching time on relative growth rate and feed intake observed in immediately fed chicks were eliminated by the 48 h feed delay. The yolk utilization after hatch was faster for the late hatchers up to biological day 2 regardless of the feeding treatments. Hatching muscle glycogen content was higher in the late hatchers compared with that of their early counterparts at hatch and at biological day 2 independent of feeding treatment. Moreover, the liver glycogen content of the late hatchers was also higher at hatch. For the immediately fed chicks, the proportional breast muscle weight of the late hatchers was higher at biological day 2 and 5. For the starved chicks, on the other hand, this effect was only observed after they had access to feed (biological day 5). The different plasma T3 levels at hatch may have contributed to the different post hatch performance. It is concluded that the spread of hatch influenced post hatch performance, especially appetite and growth at least until day 5. Moreover, the delay in feed access interacted with the hatching time and caused adverse effects on the post hatch performance.

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To examine the importance of albumen as a protein source during embryonic development on the posthatch performance of laying hens, 3 mL of the albumen was removed. At hatch, no difference in BW could be observed. Chicks from the albumen-deprived group had a lower residual yolk weight due to higher yolk utilization. During the rearing phase (hatch to 17 wk of age), the BW of the albumen-deprived pullets was lower compared with the control and sham pullets. The feed intake of the albumen-deprived pullets was also lower than the control pullets. However, during the laying phase (18 to 55 wk of age) these hens exceeded the control and sham hens in BW, although this was not accompanied by a higher feed intake. The albumen-deprived hens exhibited a lower egg production capacity as demonstrated by the reduced egg weight, laying rate, and egg mass and increased number of second grade eggs. In addition, the eggs laid by the albumen-deprived hens had a higher proportional yolk and lower proportional albumen weight. In conclusion, prenatal protein deprivation by albumen removal caused a long-lasting programming effect, possibly by differences in energy allocation, in favor of growth and maintenance and impairing reproductive performance.

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Natural killer-cell activity for K562 target cells was measured in 13 patients with severe combined immunodeficiency before bone marrow transplantation. Both unseparated peripheral blood mononuclear cells and sorted cell subsets (B73.1 positive, B73.1 negative, OKT3 positive, OKT3 negative) were tested. Heterogeneity of natural killer-cell activity was observed, the level of which did not correlate with the usual subdivision of severe combined immunodeficiency, as defined by a scientific group on immunodeficiency for the WHO. In those patients in whom natural killer-cell activity was observed in unseparated cells, testing of this function in sorted cell subsets revealed some unexpected findings. In three of four patients, B73.1-negative cells showed remarkable natural killer-cell activity. In addition, in one of these patients, no activity was observed in the B73.1-positive cells.

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