Keratinase

Protease catalyzes peptide bond and hydrolyzes protein into peptone, keratinase enzyme, polypeptide and amino acid. As a kind of alkaline serine protease, keratinase not only has the function of normal alkaline protease, but also can break down disulfide bond and disintegrate keratin.

Definition and Dosage of Activity Keratinase
One unit (U) of protease activity is defined as the amount of enzyme which liberates 1 μg tyrosine per minute from substrate casein at 40℃ and pH 10.5 under the conditions of the test.
Recommended dosage is 50-100g/t with 50000 U/g in complete feed.

Functions of Keratinase Products
1. Supplement the deficiency of endogenous protease for animal.
2. Increase the digestibility of protein and amino acid in poultry and swine feed ingredients.
3. Degrade the trysin inhibitor and lectin, this is what endogenous protease can’t do.
4. Optimized the use of lower digestibility feed ingredient e.g corn, sorghum, feather meal,soybean meal and blood plasma powder.
5. Creat a better environment for animal and decrease pollution from nitrogen for human.

Application of Keratinase
1.The matrix value of keratinase (100g/t)
Crude protein, % 5400 0.54
Lysine, % 150 0.015
Methionine, % 180 0.018
Cystine, % 150 0.015
Threonine, % 210 0.021
Tryptophane, % 90 0.009
Isoleucine , % 150 0.015
Arginine, % 285 0.0285
Valine, % 255 0.0255
Alkaline Protease Alkaline protease works on most of the peptide bonds therefore can hydrolyze diversified proteins and save the protein resource.

2. Application case: Improve the performance and digestibility of nutrients.
Experimental animal: 840 one-day-old AA broilers, 6×35 broilers/treatment.
Experimental design:
Table1. Experimental design
Item Diet
PC Basal diet
NC Basal diet-0.5% crude protein
Group I NC+125g/t competitor
Group II NC+100g/t Keratinase(30000U/g)
Experimental cycle: 42 days
Results:
Table2 Effect of each treatment on the growth performance of AA broilers (g, %)
Items PC NC Group I Group II
Initial weight,g 62.79¯0.31 62.58¯0.29 62.56¯0.33 62.33¯0.27
1-21days
21stAG,g 986.16ab¯10.08 977.41b¯8.22 1013.59ab¯25.72 997.17ab¯10.53
ADFI,g 62.08¯ 1.43 60.93¯1.10 62.09¯2.04 58.71¯2.12
ADG,g 43.94¯0.47 43.45¯0.39 45.12¯1.29 44.33¯0.53
F/G 1.41¯0.03 1.40¯0.03 1.38¯0.05 1.33¯0.04
Death rate,% 1.43¯1.57 3.45¯2.21 5.38¯6.24 3.33¯5.24
22-42days
22ndAG,g 1140.08¯1.30 1135.33¯5.97 1136.73¯7.06 1138.33¯5.41
42ndAG,g 2985.77¯41.56 2971.06¯47.61 3058.21¯58.29 3010.25¯44.17
ADFI,g 179.00¯3.12 178.64¯2.86 175.81¯3.64 174.22¯2.64
ADG,g 87.88¯2.01 87.42¯2.43 91.50¯2.85 89.14¯2.20
F/G 2.04¯0.07 2.05¯0.03 1.93¯0.05 1.96¯0.06
Death rate,% 2.00¯2.19 1.33¯2.07 0.67¯1.63 1.33¯2.07
1-42days
ADFI,g 120.51¯2.39 119.78¯1.63 118.94¯2.01 116.47¯1.60
ADG,g 69.59¯0.98 69.25¯1.13 71.32¯1.39 70.18¯1.05
F/G 1.73¯0.02 1.73¯0.02 1.67¯0.02 1.66¯0.03
Death rate,% 3.43¯3.76 4.78¯1.73 6.05¯5.74 4.67¯4.59

Note: In the same row, values with different small letter superscripts mean significant difference(P<0.05).

Conclusion of Keratinase
On the basis of these results, it is concluded that the supplement of keratinase into a low CP diet was as effective as normal level in broiler. As shown in diagram 1, keratinase improve the digestibility of dry matter, crude protein, crude fat, general energy and apparent metabolic energy. And in table 4, karatinase has a positive effect on the amino acids digestibility. In this experiment, it is appeared that karatinase improve the growth performance of broiler by increase average diary gain and feed conversion rate.

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