PSXIV-2 Influences of glycerol and bypass fat supplementation on performance of early fattening Hanwoo steers under heat stress

This study was conducted to determine the influence of glycerol and bypass fat supplementation on growth performance of early fattening Hanwoo steers under heat stress. Thirty-six Hanwoo steers were randomly allocated into 4 treatments based on BW and age for 112 days from the beginning of July to the end of October 2020. Experimental treatments were divided into four by the type of energy supplements: Control (CP, 14%; TDN 71.9), glycerol addition (GL; CP, 14%; TDN 74.9), bypass fat addition (BF; CP, 14%; TDN 74.9), and glycerol plus bypass fat additive (GL+BF; CP, 14%; TDN 74.9). During the experimental period, automatic temperature-humidity recorders were used for measuring every 10 minutes in the pen. The temperature-humidity index (THI) range of the 1st and 2nd periods was recorded above the threshold (THI 75~77) level based on the Korean beef heat stress index, and the average THI of the 2nd period was 79.91, being the mild-moderate (THI 78~81) level. The dry matter intake (DMI) and average daily gain (ADG) did not show significant differences in all treatments during the whole period. The feed conversion ratio (FCR) during 1st and 2nd periods showed the same pattern because FCR is related to DMI and ADG. Additionally, the rectal temperature showed no significant difference in all treatments, but a significant difference in each period (P < 0.05). The results demonstrated that early fattening Hanwoo steers under mild-moderate stress did not affect DMI and productivity but 9.8% of GL or 1.9% BF in a concentrate only could be included in Hanwoo steers diets without decreasing palatability. In addition, increasing the energy content in the feed by 5% did not lead to a difference in productivity. Further studies would be needed on the effect of increasing the energy density on productivity under more severe thermal stress conditions.

Influence of rumen bypass fat fed with total mixed ration on growth performance in Nili-Ravi buffalo calves

This study was conducted to know the influence of rumen bypass fat supplement on growth performance of Nili-Ravi mal buffalo calves. Nili Ravi buffalo male calves (n=12) were randlomly selected and divided into two groups i.e., A and B based on two different levels of age. These groups (A and B) were further divided into two respective subgroups i.e., A1, A2 and B1, B2. Sub groups A1 and BI served as control (without supplement) whilst subgroups A2 and B2 were fed RBF supplement (at the rate of 2.35% of dry matter intake) with basel diet with total mixed ration. Results showed no statistical difference (P>0.05) in dry matter intake, body weight gain and body condition score on rumen bypass fat supplementation. In blood metabolites, rumen bypass fat supplementation increased (P<0.05) blood triglyceride and cholesterol levels, however, it reduced (P<0.05) blood glucose level in Nili-Ravi buffalo male calves. This study suggests that supplementation of rumen bypass fat at the rate of 2.35% per day in TMR possess no impact on growth performance parameters in Nili Ravi buffalo male calves.

Insect fat in animal nutrition – a review

The aim of this review is to discuss the usage of insect fats as an energy source in animal nutrition. Insects are a rich carrier of proteins, fat, and minerals. They are successfully introduced in animal diets (poultry, swine, rabbits, fish, and pets) as a source of many nutrients, including energy and essential fatty acids (FAs). The insects’ fat content and quality are highly affected by the type of substrate provided to the insects during the rearing period. The majority of the studies have shown that insect fats may be used as promising substitutes for conventional energy resources in animal nutrition without adverse effects on growth performance and feed utilization. They can positively affect meat quality by increasing the level of long-chain polyunsaturated FAs but may also positively influence animals by regulating the gut microbiota and stimulating the immune system. In conclusion, insect fat supplementation showed promising results in terms of their application in animal nutrition. However, compared to insect protein application, very few studies have been performed on insect fats. Therefore, because of the fat quality and content of insects, there is a need to extend experimentation regarding their implementation in animals’ diets as a replacement for conventional dietary energy resources.

Antimicrobial Effects of Black Soldier Fly and Yellow Mealworm Fats and Their Impact on Gut Microbiota of Growing Rabbits

This study aimed to evaluate the in vitro antimicrobial activities of two types of insect fats extracted from black soldier fly larvae (HI, Hermetia illucens L.) and yellow mealworm larvae (TM, Tenebrio molitor L.) and their effects as dietary replacement of soybean oil (S) on cecal fermentation pattern, and fecal and cecal microbiota in rabbits. A total of 120 weaned rabbits were randomly allotted to three dietary treatments (40 rabbits/group) —a control diet (C diet) containing 1.5% of S and two experimental diets (HI diet (HID) and TM diet (TMD)), where S was totally substituted by HI or TM fats during the whole trial that lasted 41 days. Regarding the in vitro antimicrobial activities, HI and TM fats did not show any effects on Salmonella growth. Yersinia enterocolitica showed significantly lower growth when challenged with HI fats than the controls. The insect fat supplementation in rabbit diets increased the contents of the cecal volatile fatty acids when compared to the control group. A metataxonomic approach was adopted to investigate the shift in the microbial composition as a function of the dietary insect fat supplementation. The microbiota did not show a clear separation as a function of the inclusion, even if a specific microbial signature was observed. Indeed, HI and TM fat supplementation enriched the presence of Akkermansia that was found to be correlated with NH3-N concentration. An increase in Ruminococcus, which can improve the immune response of the host, was also observed. This study confirms the potential of HI and TM fats as antibacterial feed ingredients with a positive influence on the rabbit cecal microbiota, thus supporting the possibility of including HI and TM fats in rabbit diets.