**3.12 Algae**

*Advances in Poultry Nutrition Research*

Feathers are considering as an industrial waste resulted during birds processing in slaughter houses. Several million tons of feathers are generated from the poultry processing industry are disposed as a waste [29, 30]. Feather meal contains about 85% crude protein, 5% cysteine and 3000 kcal/kg metabolizable energy. The cysteine availability is about 60% depending on the processing conditions [4]. Usually, feathers are partially dried, and hence steam-treated to introduce hydrolysis. However, the extreme temperature will lead to destruct the amino acids, especially lysine. Therefore, leads to reduce the amino acids digestibility. To overcome this problem, the use of keratinase enzyme may play an important role in improving the protein digestibility [29] and poultry performance [4]. In addition, fermentation with bacteria-degrading keratin such as *Bacillus licheniformis* for five days at 50°C can produces a fermented product comparable in nutritional value to

Some reports mentioned that *B. subtilis* and *Aspergillus fumigatus* had an ability to degrade keratin in feathers [30]. Feather meal can be included in poultry diets at 2–3%. Nevertheless, the fermented feather meal may give promised results in poultry nutrition, and therefore it would be an additional commercial benefit for

Insects can be used to produce cheap source of protein. It is known that insects are considered as a natural food for birds. Insects are rich in protein (40–76%) and essential amino acids [31], particularly sulfur containing amino acids [32]. Insects meal are usually featuring on high fat content [31]. Therefore, microbial deterioration and lipid oxidation should be considered during storage [33]. Ssepuuya et al. [34] indicated that insects meal may replace the conventional protein sources by 10–100% without any negative growth performance whether in fish or poultry. It was also mentioned by Kareem et al. [31] that the incorporation of black soldier fly larvae to broiler diets up to 10% had no negative effect in their growth performance under humid tropical environment. In addition, no adverse effects on growth performance, carcass characteristics, hematological and serum biochemical indices in growing Japanese quail when meat and bone meal replaced with *Spodoptera littorails* in their diets [35]. It was claimed by Neumann et al. [36] that partly adding defatted insects meal of *Hermetia illucens* larvae in broiler diets – 26% and 22% in starter and grower phase, respectively – were acceptable. In terms of meat quality, it was reported that complete substitution of soybean meal by *Hermetia illucens* led to inducing lipid oxidation in broiler meat [37]. This was attributed to the high content

the poultry industry by replacing part of soybean meal in poultry feeds.

of poly unsaturated fatty acids (PUFA) in *Hermetia illucens*.

Earthworms are a natural source of protein for poultry raised in free-range system. Earthworm can produced even in small-scale system. Earthworms species require a temperature ranging from 15 to 25°C, and 60–85% soil moisture content [38]. It can be considered as an alternative source of protein (64–76%) [39]. At the same time, it can be degrade animal manure to clean the environment. It was reported that the total essential amino acids in earthworms are comparable with egg protein. Moreover, the omega – 3 PUFA are quite high and similar to that of some fish oil [40]. It was mentioned by Parolini et al. [38] that earthworms contain

**3.9 Feather meal**

soybean meal [4].

**3.10 Insects and worms**

**26**

**3.11 Earthworms**

Algae represent an important source of unconventional protein (50–60%), oils, vitamins, minerals, antioxidant and colorants [41], carotenoids, omega-3 and omega-6 PUFA [42, 43]. Some types of algae contain up to 76% crude protein [44]. In terms of nutrition, algae were used in broiler diets up to 16% without adverse effects. On the other hand, it was a replacement for approximately 60% of soybean meal and 40% of animal vegetable blended fat into practical broiler diets [44].

The most common species of algae used in poultry nutrition are *chlorella* and *Spirulina*. It was reported by Moury et al. [45] that supplementation of *Spirulina platensis* in broiler diets may completely replace the incorporation of vitamin-mineral premix. Moreover, it can be substitute the antibiotic usage in animals [46].

It is reported that algae can be a good option for 100% organic poultry feed [47]. Neumann et al. [36] reported that incorporation of *Spirulina platensis* at 21% and 17% in starter and grower phase, respectively was acceptable. However, nutritionists have to pay attention to the presence of PUFA in algae which may affect the meat quality of broilers and lead to lipid oxidation. Gkarane et al. [37] mentioned that complete substitution of soybean meal in broiler diets by *Arthrospira platensis* influenced the meat quality and led to lipid oxidation.
