In a pig study, vaccinating against the hormone FSH made the animals eat more efficiently and store less fat, while also changing some meat quality traits. The effect was stronger than a similar vaccine against GnRH. However, the work was done in castrated male pigs, not people, so the findings are only a hint that lowering FSH might affect body fat.

Previous studies have demonstrated that follicle-stimulating hormone (FSH) plays a critical role in promoting adipogenesis. Surgical castration results in elevated FSH concentrations in pigs, and is accompanied by reduced feed efficiency. This study aimed to investigate the effects of a novel FSH vaccine comprising FSH&#x3b2;13AA-tandem-ovalbumin conjugate on growth performance and meat quality in barrows. Twenty-four barrows with initial body weight of 32.54 &#xb1; 1.90 kg and 12-week age, were randomly assigned to three groups: Placebo-immunized, GnRH-immunized, and FSH-immunized. At three weeks after booster immunization, the FSH-immunized group exhibited significantly improved feed efficiency compared to GnRH-immunized barrows. Compared to the Placebo-immunized group, GnRH and FSH vaccination reduced average backfat thickness by 0.90% and 4.55%, abdominal fat weight by 3.49% and 10.56%, and abdominal fat percentage by 4.09% and 11.95%, respectively. Moreover, the FSH-immunized group showed a significant increase in liver weight relative to the Placebo-immunized group. In addition, compared with the control group, at slaughter FSH vaccination significantly increased muscle pH at 45 min, drip loss at 24 h, and shear force (<i>p</i> &lt; 0.05). These results demonstrate that active immunization against FSH in barrows can enhance feed efficiency and reduce adiposity, as well as influence the meat quality.