Modern Applied Science; Vol. 8, No. 4; 2014 ISSN 1913-1844 E-ISSN 1913-1852 Published by Canadian Center of Science and Education 97 Protein and Fiber Profiles of Cottonseed from Upland Cotton with Different Fertilizations Zhongqi He 1 , Hailin Zhang 2 , Daniel C. Olk 3 , Mark Shankle 4 , Thomas R. Way 5 & Haile Tewolde 6 1 USDA-ARS, Southern Regional Research Center, 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA 2 Dept. of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA 3 USDA-ARS, National Laboratory for Agriculture and the Environment, Ames, IA 50011, USA 4 Pontotoc Ridge-Flatwoods Branch Experiment Station, Mississippi State Univ., Pontotoc, MS 38863, USA 5 USDA-ARS, National Soil Dynamics Laboratory, Auburn, AL 36832, USA 6 USDA-ARS, Crop Science Research Laboratory, Mississippi State, MS 39762, USA Correspondence: Zhongqi He, USDA-ARS, Southern Regional Research Center, 1100 Robert E. Lee Blvd., New Orleans, LA 70124, USA. Tel: 1-504-286-4516. Fax: 1-504-286-4367. E-mail: Zhongqi.He@ars.usda.gov Received: April 21, 2014 Accepted: May 5, 2014 Online Published: June 25, 2014 doi:10.5539/mas.v8n4p97 URL: http://dx.doi.org/10.5539/mas.v8n4p97 Abstract Whole cottonseed and its derived products can be used as human food, animal feed, and industrial raw material. Chemical composition of cottonseed is one of the critical parameters for evaluating its quality and potential end use. Especially, protein and dietary fibers are two desirable nutritional properties of cottonseed for animal feed. In this study, we determined their contents in cottonseed harvested from different fertilization managements with or without wheat cover crop in two consecutive years. Seed content of crude protein increased in the order of no fertilizer ≤ poultry litter ≤ chemical fertilizer. Both neutral and acid detergent fiber profiles were affected by fertilization and planting year/cover crop in an order reversing that of crude protein. Few statistically significant (P>0.05) impacts were observed on the content of acid detergent lignin. Observations derived from this work will provide information on nutritional value and digestibility of cottonseed as affected by cropping management practices. Keywords: cottonseed, poultry litter, amino acid, neutral detergent fiber, acid detergent fiber 1. Introduction Cotton (Gossypium hirsutum L.) is a major crop in the world (Bellaloui and Turley, 2013). For every 100 kg of lint fiber ginned from cotton, 150 kg of cottonseed is produced (Yu et al., 2012). Thus, cottonseed is an abundant resource for oil, meal and protein for human consumption, animal feed, and industrial raw material (Coppock et al., 1987; Gao et al., 2010; He et al., 2013a; 2014a; 2014b; Kandasamy et al., 2008; Zhang et al., 2009). The chemical composition is an important parameter in evaluating cottonseed quality for these different applications. In a previous research (He et al., 2013b), we collected the cottonseed samples in two successive years from cotton grown in a Falkner silt loam soil in northeastern Mississippi, USA. The cotton crop was fertilized with poultry litter (PL) and chemical inorganic fertilizer (CIF) with or without wheat cover crop. We determined the ash and elemental contents of these samples. Whereas cover crop did not significantly impact the elemental composition of cottonseed, fertilization decreased Ca, but increased Fe and Mn contents. The CIF treatment decreased but PL fertilization increased P, Mg, Cu, and ash contents. Regression analysis suggested that P, Mg, and K contributed to the increase of ash content, probably in the form of the mixture of K/Mg phytate compounds. Crude protein and dietary fiber profiles of cottonseed are important parameters in evaluating the nutrient content of cottonseed (Coppock et al., 1987; Myer, 2012). Amino acids in feedstuff are divided into essential amino acids and nonessential amino acids (Edmunds et al., 2013). The nutrient value of cottonseed protein might be dependent not only on the total protein content, but also on the level of essential amino acids (Bertrand et al., 2005). Neutral detergent fiber (NDF) is related to feed intake and acid detergent fiber (ADF) estimates feed digestibility, so both ADF and NDF are useful measures of relative feed value, and are frequently used to