feather meal
{{Short description|Poultry feather product}}
{{refimprove|date=September 2007}}
Feather meal or Feather powder, is a byproduct of processing poultry; it is made from poultry feathers by partially grinding them under elevated heat and pressure, and then grinding and drying. Although total nitrogen levels are fairly high (up to 12%), the bioavailability of this nitrogen may be low if not hydrolyzed beforehand. Feather meal is used in formulated animal feed and in organic fertilizer.
Worldwide, approximately 50 billion chickens were used for human consumption in 2014.{{cite web|url=https://www.weforum.org/agenda/2019/02/chart-of-the-day-this-is-how-many-animals-we-eat-each-year/|title=How many animals we eat each year|date=8 Feb 2019|author-given=Alex|author-surname=Thornton|publisher=World Economic Forum}} The feather from poultry slaughtering is traditionally treated as waste, with carbon emissions associated with its disposal. Reusing feather meal produces extra value while reducing carbon emissions.
Animal feed
When used as animal feed, the indigestible keratin must be broken down (partially hydrolyzed) to become digestible for animals. One process for doing this is called rendering: steam pressure cookers with temperatures over {{cvt|140|°C}} are used to "cook" and sterilize the feathers. It is then dried, cooled and ground into a powder for use as a protein source for animal feed (mostly ruminants and fish).
There are many other ways to achieve hydrolysis such as acid treatment, fermentation, and enzyme-processing.{{cite web |title=Feather meal |url=https://www.feedipedia.org/node/213 |website=Feedipedia |language=en}}
Plant fertilizer
Feather meal contains a large amount of nitrogen (15%) and sulfur (2.4%). It is rich in plant micronutrients such as iron and zinc.{{cite journal |last1=Popko |first1=Małgorzata |last2=Wilk |first2=Radosław |last3=Górecka |first3=Helena |last4=Chojnacka |first4=Katarzyna |last5=Górecki |first5=Henryk |title=Assessment of New NKSMg Fertilizer Based on Protein Hydrolysate of Keratin in Pot Experiments |journal=Polish Journal of Environmental Studies |date=2015 |volume=24 |pages=1765–1772 |doi=10.15244/pjoes/36823|doi-access=free }}{{rp|Table 3}} Being neither synthetic or petroleum-based, it is considered an organic fertilizer.
Native (non-hydrolyzed) feather meal is a semi slow-release fertilizer. The nitrogen is slowly released through decomposition by soil microbes. It is not water-soluble and hence does not make a good liquid fertilizer.{{cite journal |last1=Hadas |first1=Aviva |last2=Kautsky |first2=Larissa |title=Feather meal, a semi-slow-release nitrogen fertilizer for organic farming |journal=Fertilizer Research |date=1994 |volume=38 |issue=2 |pages=165–170 |doi=10.1007/BF00748776}} When adding it to a garden as a nitrogen source, it must be blended into the soil to start the decomposition to make the nitrogenous compounds available to the plants.
Being high-nitrogen fertilizers, both types of feather meal are useful for increasing the growth of green leaves. Both are also good for encouraging the growth of microbes, improving soil structure,{{cite journal |last1=Bhari |first1=R |last2=Kaur |first2=M |last3=Sarup Singh |first3=R |title=Chicken Feather Waste Hydrolysate as a Superior Biofertilizer in Agroindustry. |journal=Current microbiology |date=June 2021 |volume=78 |issue=6 |pages=2212-2230 |doi=10.1007/s00284-021-02491-z |pmid=33903939}} and activating the composting process.
Issues
Some countries allow or allowed the addition of organoarsenic drugs such as roxarsone (a coccidiostat) to chicken feed. A 2012 study found that the use of feather meal may contribute to inorganic arsenic exposure in humans. It examined feathers from the US and China, which both allowed the use of roxarsone at the time.{{Cite journal|title = Arsenic species in poultry feather meal|journal = The Science of the Total Environment|date = 2012-02-15|issn = 1879-1026|pmid = 22244353|pages = 183–188|volume = 417-418|doi = 10.1016/j.scitotenv.2011.12.022|first1 = K. E.|last1 = Nachman|first2 = G.|last2 = Raber|first3 = K. A.|last3 = Francesconi|first4 = A.|last4 = Navas-Acien|first5 = D. C.|last5 = Love|bibcode = 2012ScTEn.417..183N}} The US banned its use in 2013.{{cite news | author = U.S. Food and Drug Administration | url = https://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm370568.htm | archive-url = https://web.archive.org/web/20131022074630/http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm370568.htm | url-status = dead | archive-date = October 22, 2013 | title = FDA Response to Citizen Petition on Arsenic-based Animal Drugs | date = September 20, 2011}} A 2021 Chinese study found significantly elevated levels of arsenic in soil around chicken farms, though still at an amount with negligible risks for human health.{{cite journal |last1=Liu |first1=Yaci |last2=Tian |first2=Xia |last3=Cao |first3=Shengwei |last4=Li |first4=Yi |last5=Dong |first5=Huijun |last6=Li |first6=Yasong |title=Pollution characteristics and health risk assessment of arsenic transformed from feed additive organoarsenicals around chicken farms on the North China Plain |journal=Chemosphere |date=September 2021 |volume=278 |pages=130438 |doi=10.1016/j.chemosphere.2021.130438}}
Antibiotics and other drugs fed to chicken also end up in feathers. Some of these drugs are not broken down during rendering. The antibiotic residue is enough to cause statistically significant (p = 0.01) inhibition in the growth of non-resistant bacteria, while having no effect on resistant bacteria.{{cite journal |last1=Love |first1=D. C. |last2=Halden |first2=R. U. |last3=Davis |first3=M. F. |last4=Nachman |first4=K. E. |title=Feather Meal: A Previously Unrecognized Route for Reentry into the Food Supply of Multiple Pharmaceuticals and Personal Care Products (PPCPs) |journal=Environmental Science & Technology |date=3 April 2012 |volume=46 |issue=7 |pages=3795–3802 |doi=10.1021/es203970e}} Alarmingly, some US samples show traces of fluoroquinolone antibiotics, which were banned by the FDA for poultry use 7 years before the paper's publication.{{cite web|url=http://scienceblogs.com/aetiology/2012/04/05/waste-not-want-not-poultry-fea/|title=Waste not, want not? Poultry "feather meal" as another source of antibiotics in feed|first=Tara C.|last=Smith|date=April 5, 2012|website=ScienceBlogs}}
See also
References
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Sources
- [https://web.archive.org/web/20110103135037/http://www.organicgardeninfo.com/feather-meal.html Organic gardening information]
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