Enhancement of Productive Performance, Bone Physical Characteristics, and Mineralization of Laying Hens during the Post-Peak Period by Genistein.

Genistein (GEN), a soybean isoflavone, is structurally and functionally similar to endogenous estrogen; therefore, it has the potential to enhance estradiol properties. This study aimed to evaluate the effects of GEN on the reproductive performance and bone status of laying hens. In total, 80 Hy-line W-36 (40 weeks old, the late stage of egg production cycle) with an initial body weight of 1,230±15.8 g (Mean±S.E.M), similar egg production, and egg weight were randomly assigned into two groups with 10 replicates and 4 birds in each replicate (40 laying hens per group). Laying hen diets had 0 (control) and 20 mg/kg GEN (white powder, Sichuan Guanghan co. Ltd., purity of 98.5%) for 6 weeks (41 to 46). At the end of the experiment, 20 hens (one hen from each replicate) were slaughtered, and the samples of bone and shell gland (approximately 50 mg) were surgically taken immediately after slaughter for Real-time PCR. The results indicated that dietary GEN increased egg production, feed intake, and egg mass; however, it decreased egg weight (p <0.05). Furthermore, the feed conversion ratio was greater in birds received GEN, compared to those in the control group (p <0.05). GEN enhanced egg quality indices included eggshell strength, thickness, and percentage (p <0.05). Mechanical properties of the tibia, such as weight, length, and breaking strength were also increased by GEN (p <0.05). Moreover, dietary GEN increased the calcium content of the tibia (p <0.05). The mRNA expression of Calbindin-D28k (CaBP-D28k) and transient receptor potential vanilloid channel type 6 (TRPV6) upregulated in eggshell glands of hens treated with GEN paralleled to the controls (p <0.05). In conclusion, the findings of the present study showed that GEN had the potential to improve the bone physical characteristics, mineralization, and the productive performance of Hy-line W-36 laying hens in their post-peak period.

Administration of prostaglandin F2α 14 d before initiating a G6G or a G7G timed artificial insemination protocol increased circulating progesterone prior to artificial insemination and reduced pregnancy loss in multiparous Holstein cows.

The objectives of this study were to determine the effect of PGF2α treatment 14 d before the initiation of a G6G or G7G (PGF2α, 2 d, GnRH, 6 or 7 d, Ovsynch) protocol on ovarian response, synchronization protocol on ovarian response, progesterone (P4) concentration, pregnancy per AI (P/AI), and pregnancy loss in multiparous Holstein cows. Cows (3.6±1.1 lactations and yielding >30kg/d of milk) were randomly assigned to 1 of 4 timed artificial insemination (TAI) protocols: 1) G6G (n=240), one injection of PGF2α, GnRH 2 d later and a 7-d Ovsynch protocol (GnRH, 7 d, PGF2α, 56 h, GnRH 16 h TAI) was initiated 6 d later; 2) PG6G (n=250), PGF2α 14 d before the initiation of the G6G protocol; 3) G7G (n=200), one injection of PGF2α, GnRH 2 d later, and a 7-d Ovsynch protocol initiated 7 d later; and (4) PG7G (n=200), a PGF2α injection 14 d before the initiation of the G7G protocol. Blood samples from a subset of 269 cows were collected at the times of first and second GnRH, and PGF2α of the Ovsynch protocol to measure P4. Ultrasound examinations were performed to evaluate ovarian response to GnRH and PGF2α of Ovsynch, and to determine pregnancy status at 32 and 60 d after TAI. The proportion of cows with high (≥1ng/mL) P4 at first GnRH of Ovsynch was greater for PG6G and PG7G compared with G6G and G7G groups (combined 79.7 vs. 59.3%). In addition, mean (±SEM) plasma P4 concentration (ng/mL) at PGF2α of Ovsynch was also greater in PG6G (6.5±0.2) and PG7G (6.7±0.3) compared with G6G (5.1±0.2) and G7G (5.0±0.2). Cows given PGF2α 14 d before initiating a G6G or a G7G TAI (PG6G and PG7G) tended to have a greater P/AI at 32 d compared with those cows not receiving PGF2α (G6G and G7G). However, P/AI at 60 d was greater in cows subjected to PG6G and PG7G protocols (31.1 vs. 39.2%), with a lower pregnancy loss between 32 and 60 d (11.65 vs. 19.7%). In summary, administration of PGF2α 14 d before initiating a G6G or a G7G TAI protocol increased P4 concentrations before artificial insemination and late embryonic/early fetal survival in multiparous Holstein cows.