The objective of this study was to evaluate effects of feeding methods on in vitro ruminal fermentation, total gas and methane production in Hanwoo steers. Six Hanwoo steers fitted with rumen cannula (430 ± 21 kg of body weight) were randomly assigned to one of three feeding systems: 1) feeding forage 1 hour after concentrate, 2) feeding concentrate 1 hour after forage, 3) feeding mixed ration. Rumen fluid sampled from each animals was incubated 24 hours with maize or timothy substrates in in vitro. Ruminal pH was increased in feeding method 2 or maize substrate than that of other methods or timothy substrate (P < 0.001). The production of total volatile fatty acid, acetate, propionate, butyrate, and valerate were increased when steers fed diets using feeding method 1 or rumen fluid was incubated with maize substrate (P < 0.001). Increased production of total gas and methane was observed in feeding method 1 and maize substrate compared to those of other methods or timothy substrate (P < 0.001). Due to the inconsistent results between ruminal fermentation and gas production in this study, further research is required to estimate effects of feeding method on enteric fermentation and gas production in in vivo.

메탄가스는 주요 온실가스 중 하나로 반추동물의 장내발효를 통해 발생하며, 이러한 경로의 메탄가스는 대한민국 축산부문 총 온실가스 발생량의 40% 이상을 차지한다. 이런 이유로 많은 연구자들은 반추동물에서 발생하는 메탄생성량을 줄이기 위한 시도를 계속해 왔다. 본 연구는 반추동물의 메탄발생량을 측정하기 위해 호흡대사챔버를 개발하고 호흡대사챔버의 정확성을 검증하기 위해 실시하였다. 호흡대사챔버는 25.4 m3 크기로 스테인리 스 플레이트로 내부를 완전히 밀폐하였다. 직경 Φ100의 공기 유입관과 배출관을 설치하였고, 공기 배출관에 에어모터를 설치하여 내부공기를 제거함과 동시에 유입관을 통해 배출된 만큼의 공기가 외부에서 유입되도록 하였다. 챔버 내 메탄가스 회수기능을 검증하기 위해 메탄표준가스 5L를 각 챔버에 주입하여 균일하게 확산시킨 후, 챔버 내부의 공기를 900 L/min의 속도로 제거하였다. 제거된 공기의 메탄가스 농도를 연속적으로 측정하여 주입된 메탄가스와 비교함으로써 회수율을 평가하였다. 챔버 내 표준가스는 평균 100분에 완전히 제거되었으며, 메탄가스의 회수율은 평균 109 ± 6.7%로 측정되었다. 호흡대사챔버의 실제 이용성을 평가하기 위해, 평균체중 581.9 ± 33.8 kg 의 한우 거세우 4두에게 비육후기 배합사료 9 kg과 볏짚 1 kg을 급여하며 메탄발생량을 측정하였다. 한우의 장내발효에 의한 메탄발생량은 평균 236.4 ± 105.44 L/day로 측정되었다. 본 연구에서 개발·검증한 호흡대사챔버는 국내 한우의 장내발효 메탄가스발생량 측정 시험에 적용 가능할 것이다.

We investigate the effects of the immune function (HI titer) in broilers fed diets containing Hermetia illucens (H. illucens) peptide extract over a 40-day period. Twenty-four broiler chicks (Arbor Acres, 1 d old) were divided into four groups and fed different diets (control, 0.1%, 0.5%, and 1% H. illucens peptide extract). To evaluate HI titer, all broilers were vaccinated with H9H2 vaccine subcutaneously on the lateral thorax, according to the manufacturer’s recommendations. Similar HI titer was observed with 1% H. illucens peptide extract treatment compared to the control after 40 days (p>0.01). Groups fed 0.5% H. illucens peptide extract demonstrated the most effective immune effects (p<0.01), followed by groups fed 0.1% H. illucens peptide extract. In conclusion, using 0.1% or 0.5% H. illucens peptide extract before or after vaccination improved HI titer immune function in broilers.

This study was conducted to evaluate the growth performance of broilers fed different levels of Hermetia illucens powder. A total of 400 broiler chicks (1-day old Arbor Acres) were fed commercial diets containing H. illucens powder at 0%, 0.1%, 0.5%, and 1% with four replicates (25 chicks per replicate), for 35 days. Weight gain in broilers fed diets containing different levels of H. illucens powder increased significantly at 28 and 35 days, compared with that of the control (p<0.05). However, feed intake and mortality showed no differences among the treatments as a function of time. At 21, 28, and 35 days, broilers fed different levels of H. illucens powder had lower feed conversion rates (p<0.05) than their counterparts fed the control diet. In conclusion, 0.5% H. illucens powder is the optimal level for improved weight gain and feed conversion.