Effect of dietary calcium and phosphorus decrement with vitamin D3 or fennel extract on hatchability, chick quality and embryonic mortality in post molted broiler breeder

Plants (specially herbs) have been used as food for medicinal purposes for centuries and some of them have played a significant role in maintaining human health and improving the quality of human life for thousands of years (Osman et al. 2005). Aromatic plants have been used traditionally in therapy against some diseases for a long time in the world. In different herbs, a wide variety of active phytochemicals, including the flavonoids, terpeniods, lignans, sulfides, polyphenolics, carotenoids, coumarins, saponins, plant sterols and phthalides have been identified (Craig 1999). Feed additives were used for broiler breeders to increase utilization of the limited feed allowance and, in turn, improve egg production performance, fertility, and hatchability. The addition of aromatic plants to feeds and water has been shown to improve feed intake, feed conversion ratio and carcass yield (Hertrampf 2001). Some studies stated that fennel (Foeniculumvulgaris) is one of the aromatic plants containing a high percentage of linolenic and stearic acids. In addition, fennel is characterized by the presence of 16.81% trans anethole and 47.20% Estragole with 64.01% of total sweeting components in essential oil. It is generally assumed that estrogen decrement over the production cycle, drops slowly during molt (Hoshino et al. 1988), and estrogen level increases again with the beginning of egg production cycle (Johnson, 1986). These changes underlie the egg production patterns of commercial layers, where a gradual decline in egg number from the peak reached shortly after sexual maturity, is witnessed. Hansen et al (2003) confirmed the dramatic decrease in blood estrogen concentration in hens at 70 week compared to those at peak production (~29 weeks).
Materail and In this study, the decoction (the process of boiling a substance in a liquid to extract its active ingredients) was used to preserve the active ingredients of the herb without any increase in temperature. Twenty gram of fennel seeds was mixed in 200 ml of 70% ethanol. The mixtures were then left in refrigerator overnight to release all active components from the herb and then fil-tered through gauze and evaporated under vacuum conditions at 40ºC using a rotary evaporator (Rotavapor R-114, Buchi Labortechnik AG, Flawil and Switzerland) (Saeedi et al. 2010). The completely randomize design with seven treatments (1-Contorol, 2-Ten percent decrement in calcium and phosphorus, 3-Twenty percent decrement in calcium and phosphorus, 4-As the second treatment with twenty percent increase in vitamin D3, 5-As the third treatment with twenty percent increase in vitamin D3, 6- As the second treatment supplemented with 50mg/kg FE, 7-As the third treatment supplemented with 50mg/kg FE) were used in this experiment that each treatments assigned to 4 replicates. In each pen 10 hens and 1 rooster (2×1 m2) were assigned, with 16 L:8 D lighting program and a temperature maintained close to 21̊C. Eggs were manually collected 6 times a day. Thirty-six settable eggs per pen were set for incubation biweekly. Eggs were incubated in Jamesway model Micro Pt- 100 commercial incubator. Incubator was set at 37.15 ̊C dry bulb and 29.62 ̊C wet bulb temperatures (0-19 days). Eggs were candled on day 10 of incubation for monitoring infertile eggs. All infertile eggs were opened and examined macroscopically for evidence of embryonic mortality. All unhatched eggs were analyzed for developmental stage of dead embryos. The time of embryonic death was assigned to one of four categories: early dead (≤7 days), mid-dead (8-16 days), late dead (17-21 days), and pips. Fertility was expressed as the rate of fertile eggs to total eggs set. On day 19, eggs were transferred to baskets and the baskets were placed randomly into the hatcher cabinets. Hatcher was set at 36.44 ̊C dry bulb and 32.18 ̊C wet bulb temperatures. The number of eggs that hatched was recorded at 21.5 days of incubation. Hatchability of fertile eggs was ex-pressed as the rate of hatching chicks to fertile eggs, and cumulative hatchability was expressed as percentage of hatching chicks to the total eggs set. At the end of 21.5 days of incubation, pipped eggs were recorded and real hatch was expressed as: Real Hatch= total hatched chicks / total egg - (fertile eggsꘪ楹 eggs). Real hatch parameter include some of the eggs recorded as "pipped", which survived through incubation but did not hatch; therefore, they were not included in the analysis. Such eggs were counted as if they hatched, thus causing the estimate of failure to hatch to be biased downward. Chick quality was defined as normal and abnormal chick, already described by Dziaczkowska (1980). After hatching, broiler chickens were feather-sexed for gender rate.
During the experiment hatchability, embryonic mortality, percentage of male chick, chick weight and ovarian components were evaluated. Results of this experiment showed that dietary treatments had no significant effect on the embryonic mortality and follicular hierarchy. Loss of calcium, phosphorus and vitamin D3 (treatments: 2, 3) significantly increased embryonic mortality; also, follicular hierarchy significantly decreased in the third treatment (P The results of this experiment indicated that using of fennel extract could decrease mid stage embryonic mortality same as vitamin D3.