CHEMICAL COMPOSITION AND AMINO ACID PROFILE OF DIFFERENTLY PROCESSED FEATHER MEAL

Feather wastes represent potential alternative ingredients for animal feedstuffs which can ameliorate the protein shortage for food and feed. Previous attempts to provide information about the nutrient composition of feather meal are either too complicated for rural livestock farmers in developing countries or they provided incomplete information on chemical composition. Washed feathers were subjected to different processing techniques such as pre-soaking in distilled water, wood ash, 0.3M NaOH, a mixture of wood ash and 0.3M NaOH, incubated at 37C and boiled at 150C for 60 minutes. Treated feather meals were analysed for chemical composition and amino acid profile. The overall result showed that feather meal pre-soaked with wood ash for 24 hr boiled at 150C for 60 minutes, those pre-soaked with 0.3M NaOH and wood ash incubated at 37C for 24 hr boiled at 150C for 60 minutes and raw feather meal pre-soaked in distilled water for 24 hr boiled at 150C for 60 minutes gave better results. Wood ash and 0.3M NaOH and their mixture could enhance the nutritional value of feather meal.


Introduction
Globally, feathers are produced in large quantities annually as a by-product of poultry processing (Fakhfakh et al., 2010).Feathers could account for about 6% of the live weight of the mature chicken.They are rich in a keratinous protein, which is a fibrous and insoluble protein (Swetlana and Jain, 2010).Feathers have uses in erosion control, diaper filling, biodegradable composites, green house industry, animal feeds, upholstery, artwork, paper alternatives, light-weight structural materials, water filtration fibers, fabric, aircraft and automotive industries and thermal insulation (Comis, 1998;Schmidt, 1998).Feather protein is not easily degradable, thereby affecting its digestibility and use as livestock feed.Hence, it becomes necessary to develop effective, easy and cheap processing techniques that will hydrolyse feathers.
Feather meal is rich in protein which is under-utilised for animal nutrition, particularly in the developing countries.Its major limitation is that little information exists regarding its nutrient composition as well as the effective processing techniques that could enhance its nutritional values.Previous attempts to provide information about the nutrient composition of feather meal are either too complicated for rural livestock farmers in developing countries or they provided incomplete information on chemical composition and amino acid (NRC, 1994;Cotanch et al., 2007).Several researchers have investigated chemical or enzymatic methods for the hydrolysis of feathers (Steiner et al., 1983;Onifade, 1998;Moritz and Latshaw, 2001).Wood ash is used traditionally by gardeners as a good source of potash for domestic gardens and it is used to soften food stuffs such as locust bean seeds for making seasoning.It has been reported that potassium hydroxide can be made directly from wood ash (Anonymous, 2016), potassium hydroxide made in that form is known as a caustic potash or lye.NaOH and KOH are caustic chemicals which can be interchangeably used in a variety of situations.NaOH reacts with water to give lye solution.This present study aims at creating the nutrient profile of differently processed feather meal as a substitute for protein of animal origin, particularly for monogastric animals in developing countries.

Material and Methods
The protocol used in this study was reviewed and approved by Landmark University Animal Care and Use Committee, Nigeria.All the reagents used were of analytical grade.

Processing of feather meal
Fresh feathers from 8-wk white feather broilers (arbor acre) were obtained from Landmark University Commercial Farm.They were washed severally with distilled water.Washed feathers were subjected to different processing techniques: T1 contained 10 g of raw feathers pre-soaked in distilled water for 24 hr, boiled at 150 o C for 1 hr, then dried in a circulating air-drying oven at 50 o C for 24 hr; T2 contained 10 g of feathers pre-soaked with 0.3M NaOH for 24 hr boiled at 150 o C for 1 hr then dried in a circulating air-drying oven at 50 o C for 24 hr; T3 contained 10 g of feathers pre-soaked with ash from hard wood at 12 g/L for 24 hr, boiled at 150 o C for 1 hr then dried in a circulating air-drying oven at 50 o C for 24 hr; T4 had 10 g of feathers pre-soaked with 0.3M NaOH incubated at 37 o C for 24 hr, boiled at 150 o C for 1 hr then dried in a circulating air-drying oven at 50 o C for 24 hr; T5 contained 10 g of feathers pre-soaked with wood ash incubated at 37 o C for 24 hr boiled at 150 o C for 1 hr then dried in a circulating air-drying oven at 50 o C for 24 hr; T6 contained 10 g of feathers pre-soaked with 0.3M NaOH and ash from hard wood at 12 g/L for 24 hr boiled at 150 o C for 1 hr then dried in a circulating airdrying oven at 50 o C for 24 hr; T7 contained 10 g of feather pre-soaked with 0.3M NaOH and ash from hard wood at 12 g/L incubated at 37 o C for 24 hr boiled at 150 o C for 1 hr then dried in a circulating air-drying oven at 50 o C for 24 hr; T8 contained 10 g of feathers pre-soaked with 0.3M NaOH not boiled but dried in a circulating air-drying oven at 50 o C for 24 hr; T9 contained 10 g of raw feathers not soaked, not boiled but dried in a circulating air-drying oven at 50 o C for 24 hr.Each treatment was done in triplicates.

Chemical analyses
The proximate composition and amino acid profile of differently processed feather meal were carried out using DA 7250 NIR analyser (Pertem, Sweden).

Statistical analysis
The mean values obtained for the proximate composition and amino acid profile were subjected to an analysis of variance using PROC General Linear Model of SAS (Statistical Analysis System 9.3, SAS Institute, Cary, NC, USA).Significant means were separated using Duncan's multiple range test (Duncan, 1955).Each treatment (processing technique) served as the experimental unit.Results are presented as means plus standard deviation of P<0.05 defined as significant.
When feeding feather meal processed in the above stated ways to monogastric animals, there may be a need to supplement the diet with lysine and methionine in order to boost the limiting amino acids in the diets.It has earlier been reported that feather meal contains a high proportion of sulphur amino acids with 6:1 of cystine to methionine (Cotanch et al., 2007;Liu et al., 1989;Han and Parson, 1991).Amino acids (AAs) were traditionally classified as nutritionally essential or nonessential for animals and humans based on nitrogen balance or growth.All nonessential AAs (NEAAs) were assumed to be synthesized adequately in the body as substrates to meet the needs for protein synthesis.Animal diets need the adequate amount of all essential AAs in order to optimize animal performance.If the dietary concentration of one particular amino acid is too low, others may not be used efficiently.Nutrient content of a feed determines the voluntary intake of animals, which in turn affects the growth rate, productivity and efficiency.Feed intake is depressed by a deficiency in the limiting amino acid or an excessive supply of some essential AAs [21].The need for maintenance and the need for protein accretion determine AA requirements by animals (Fuller et al., 1989).The AA in practice is expressed relative to lysine (Millet, 2012).Tryptophan supplement to a tryptophan-limiting diet has been shown to boost feed intake in piglets (Jansman et al., 2010), while low levels of valine were reported to result in lower feed intake (Mavromichalis et al., 2001;Theil et al., 2004).Low valine diets result in lower feed intake and daily gain (Millet, 2012;Lordelo et al., 2008;Wiltafsk et al., 2010).
Somatostatin has been indicated as a factor responsible for anorexia induced by valine-deficient diets (Nakahara et al., 2011).Tryptophan has been shown to compete with large neutral amino acids (LNAAs) such as leucine, isoleucine and valine for its passage through the blood-brain barrier by sharing a common transport system (Fernstrom and Wurtman, 1972).Decreased feed intake has been attributed to a low tryptophan diet which consequently affects serotonin concentration in the brain (Henry, 1992).Millet (2012), however, has observed that supplementing valine or tryptophan to a diet limiting in both AAs improves performance of pigs.
Feather meal pre-soaked with wood ash for 24 hr boiled at 150 o C for 1hr gave the best crude protein content, followed by those pre-soaked with 0.3M NaOH and wood ash incubated at 37 o C for 24 hr boiled at 150 o C for 1hr and raw feather meal pre-soaked in distilled water for 24 hr boiled at 150 o C for 1hr.In terms of amino acid profile, those pre-soaked with 0.3M NaOH and wood ash incubated at 37 o C for 24 hr boiled at 150 o C for 1hr gave the best result, comparably followed by those pre-soaked with wood ash for 24 hr boiled at 150 o C for 1hr and raw feather meal pre-soaked in distilled water for 24 hr boiled at 150 o C for 1hr.There seems to be beneficial effects of the use of wood ash and a mixture of wood ash and NaOH in the production of feather meal.However, further studies are recommended to assess the effect of the processing methods on animals' performance and digestibility.Otpad od perja predstavlja potencijalno alternativan sastojak hrane za životinje koji može pomoći u razrešavanju problema nedostatka proteina u hrani.Prethodni pokušaji da se pruže informacije o nutritivnom sastavu brašna od perja su ili previše komplikovani za stočare u zemljama u razvoju ili su pružali nepotpune podatke o hemijskom sastavu.Isprano perje je bilo podvrgnuto različitim tehnikama obrade kao što su prednatapanje u destilovanoj vodi, pepelu od drveta, 0,3M NaOH, mešavini pepela od drveta i 0,3M NaOH, inkubirano na 37 o C i kuvano na 150 o C tokom 60 minuta.Tretirano brašno od perja je analizirano radi utvrđivanja hemijskog i aminokiselinskog sastava.Ukupan rezultat je pokazao da se najbolje pokazalo brašno od perja, koje je prethodno natapano pepelom od drveta tokom 24h kuvano na 150 o C tokom 60 minuta, i ono koje je prethodno natapano u 0,3M NaOH i pepelu od drveta inkubirano na 37 o C tokom 24 h i kuvano na 150 o C tokom 60 minuta i sveže brašno od perja prethodno natapano u destilovanoj vodi tokom 24 h kuvano na 150 o C tokom 60 minuta.Pepeo od drveta i 0,3M NaOH i njihova mešavina bi mogli poboljšati hranljivu vrednost brašna od perja.

Table 1 .
Proximate composition of differently processed feather meal.
DM = dry matter, T1 = raw feather meal pre-soaked in distilled water for 24 hr boiled at 150 o C for 1hr; T2 = feather meal pre-soaked with 0.3M NaOH for 24 hr boiled at 150 o C for 1 hr; T3 = feather meal pre-soaked with wood ash for 24 hr boiled at 150 o C for 1hr; T4 = feather meal pre-soaked with 0.3M NaOH incubated at 37 o C for 24 hr boiled at 150 o C for 1hr; T5 = feather meal pre-soaked with wood ash incubated at 37 o C for 24 hr boiled at 150 o C for 1 hr; T6 = feather meal pre-soaked with 0.3M NaOH and wood ash for 24 hr boiled at 150 o C for 1hr; T7 = feather meal pre-soaked with 0.3M NaOH and wood ash incubated at 37 o C for 24 hr boiled at 150 o C for 1 hr; T8 = feather meal pre-soaked with 0.3M NaOH; T9 = raw feather meal not soaked, not boiled.Means within the same column with different superscripts are significantly (P<0.05)different.

Table 2 .
Amino acid profile of differently processed feather meal.