# A Review of Biochar Properties and Their Utilization in Crop Agriculture and Livestock Production
## 5 Biochar as a Feed Additive  
The use of char as a feed additive for farm animals have been known for some time, and the results of such supplementation among different groups of animals are, in general, affirmative. This means better digestion, feed conversion ratio, weight gain, or GHGs emission mitigation, and also as a medication against intoxication and bacteriological or viral diseases [49]. Given the above, the use of BC as a dietary inclusion for animal nutrition seems to be a promising solution, and such research direction has recently emerged. [PERSON] et al. [50] have shown that the inclusion of oak wood BC into chicken broilers' and laying hens' diets can positively influence their production performance. In the first experiment, 2.5, 5.0, and 10% (_w/w_) BC inclusions to the diet of chicken broilers were examined. Biochar amendment improved the feed conversion ratio, increased body weight gain and also the feed intake of chicken broilers during the first 21 d of the experiment. The 5% BC treatment had the most significant impact with a 23% increase in body weight gain, a 17% increase in feed intake, and a 5% improvement in the feed conversion ratio. Result for days 21 to 42 were not significant. In the second experiment, the inclusion of BC in the starter/finisher diets significantly improved the feed conversion ratio by up to 7%. At the end of the experiment, chicken broilers fed with BC showed significantly higher body weight gain (by up to 8%). In the third experiment, dietary supplementation with BC did not significantly affect any production parameters of laying hens except for the reduction of the number of cracked eggs by 65%, 38%, and 24% for 4%, 2%, and 1% (_w/w_) BC amendment, respectively. [PERSON] et al. [51] investigated the carry-over of aflat into the milk of goats fed with activated charcoal in the amount of 1% of daily dry matter intake. The use of activated charcoal significantly reduced the excretion of aflat by 76% without influencing milk composition, except Zn content. Research by [PERSON] et al. [52] showed that goats supplemented with bamboo BC at the rate of 0.5 and 1.0 g of BC per kg of goat body weight improved dry and organic matter digestibility, while 1.0 g supplementation also reduced N content in urine by 61%. In addition, young goats fed with a BC diet inclusion showed 17% increased daily body mass gain. [PERSON] et al. [53] investigated growth performance and carcass characteristics of chicken broilers fed with the addition of canarium seed and maize cob BCs (1 mm dia.). For both of the BCs, live body weight and body weight gain were improved with supplementation in a dose of 0.2%, 0.4%, and 0.6% (_w/w_) by up to 17% for 0.2% canarium BC treatment. Charcoal had no significant effect on the intestine circumference, carcass yield, and percentage of the liver, heart, and abdominal fat. Both BC additions increased pancreas weight by up to 120% for a 0.6% dose of canarium BC. Intestine density was not significantly affected by maize cob BC; however, adding 0.2% canarium BC increased intestine density by 20%. An addition of canarium BC in a dose of 0.8% and 1.0% increased creatinine levels by 18 and 86%, respectively. Maize cob BC at a dose of 1.0% also increased the creatinine level by 25%. In addition, maize cob BC depressed the weight of the gizzard by up to 28% for a 0.8% dose while canarium BC did not affect the gizzard size. [PERSON] et al. [54] fed <8 mm diameter charcoal with other supplements to dairy cows at different doses, and investigated the effect of the treatment on blood serum _C. botulinum_ ABE and CD antibody levels. A daily application of 400 g of charcoal (1-4 week of the experiment) and 200 g of charcoal with 50 mL of sauerkraut juice (11-14 week of the experiment) per entire herd significantly reduced the antibody levels by about 30% due to the absorption of _C. botulinum_ toxins in the gastrointestinal tract by the charcoal. [PERSON] et al. [55] investigated the effect of poultry litter derived BC as a diet inclusion for chicken broilers.