EFFECT OF REPLACING TREATED AND UNTREATED CORN IMPURITIES WITH UREA INSTEAD OF WHEAT BRAN ON PRODUCTIVE PERFORMANCE OF AWASSI LAMBS

The study was conducted to study the effect of replacing different levels of treated and untreated corn impurities with urea instead of wheat bran on productive performance of Awassi lambs. Wheat bran were replaced by five levels of treated and untreated corn impurities as: 44:0%, 32:11%, 20:22%, 10:32% and 0:39% bran: impurities in a 2×5 factorial experiment. Concentrated fed at 3% of live body weight as dry matter basis, while alfalfa hay was offered ad libitum. Forty Awassi lambs were used, with an initial weight of 27.45 ± 2.16 kg and 4-5 months old. All lambs were fed individually feeding for 70 days, preceded by 14 days as adaptation period. Results showed a non-significant superiority in dry matter and nutrients intake by increasing corn impurities and a highly significant increased (p<0.01) in ether extract and ash intake (g/day), with superiority of digestibility (P<0.05) of organic matter% (OM) and crude protein% (CP), feed efficiency, daily gain (g/ day) and total weight gain (kg) for feeding 30% of corn impurities treated with urea (T9). In conclusion, it is possible to use corn impurities instead of wheat bran, preferably treated with urea to increase crude protein content, degraded crude fibers and improved nutritional values.


INTRODUCTION
There are huge numbers of agro-waste or untraditional and bulky feeds that could be used in ruminants feeding.Agro or industrialwaste is defined as agricultural or industrial by-products that don't enter the production process but are associated with the main products like straw, the most widespread agricultural wastes due to direct connection with the production of strategic grains (12).Nutritional value of feeds is a paramount necessity to determine the profit yield from farming ruminants, as feeding costs 75-80% of the capital (23), Therefore, nutritionists interested in using additives to increase the production or improving nutritional value of bulky feeds through physical, chemical or biological treatments.Adding fat-soluble vitamins pre-and post-mating of ewes led to improve the reproductive performance (1), or adding vitamin E to enhance growth (15) while, Khalid and Al-Anbari ( 16) referred to enhance milk yield by adding 150 ml/ day glycerol to the rations of Holstein cows.Adding ajwain seeds to the rations enhance health and growth performance (8).In addition, the dependency of locally available fodder reduces environmental pollution, recycling and lowering production costs.Many untraditional wastes were used, Seifdavati et al. (21) used pumpkin wastes after harvest with 40% of alfalfa hay to produce good quality silage, Conceição et al. (6) replaced cactus instead of wheat bran and said it could be used with another source roughage due to the low fiber content.Babale et al. (5) mentioned that corn cobs could be replaced with corn bran up to 40% and reduced cost of production.Wheat bran has good protein content with low crude fibers, but it has a high price locally, while corn impurities is cheap with low crude protein and high fiber content, so it is very appropriate to treat with urea and incubation for 30 days at a humidity 60% in order to increase its content of crude protein and reduce the proportion of crude fibers, that's lead to improve nutritional value (11).Emmanuel et al. (9) stated that treated roughage feeds with 1% urea could positively improve dry matter intake, digestibility, growth performance and feed efficiency of growing camels.Urea hydrolysis to NH3 by rumen microorganism's enzymes within 2hours after feeding and occurs at a higher rate of NH3 (14), and could used by soaked grains with urea without side effects in contrast direct feeding of urea (24).So, if we want to increase voluntary feed intake of agro-industrial by-products treated with urea, it's preferable to provide rapid digestible energy like molasse or barley grains to create a synchronization between the release of ammonia and energy fermentation and resulted increased dry matter intake.Recycling of agricultural and industrial by-products is very important to achieve more feed for ruminants and offset the reduction of natural grazing in arid and semi-arid areas and benefit from untraditional feeds like corn impurities.In general, corn cobs formed 8 -15% as by-products of corn production, while corn impurities formed 1.2 -1.8%.In Iraq, impurities were 9557 tons from 2015 -2020 and tended to increase every year with expansion of corn production, it's inexpensive and cost 30$ per ton.Al-Ani et al. (2) found that using whey powder had no effect on blood urea comparing with urea nitrogen or expensive soya protein.Nowadays, strategies for using residues in feeds have developed feeding systems to make more profit without affecting the animals, for this reason, this study aimed to evaluate the effect of replacing treated and untreated corn impurities with urea instead of wheat bran on feed intake, digestibility, growth efficiency and feed efficiency in Awassi lambs.

MATERIALS AND METHODS
Chemical treatment and experimental feeds: Chemical treatment of corn impurities with urea (ureated corn impurities UCI) was carried out by adding urea to prepare 3.3% nitrogen (7.17% urea as dry basis ) at air temperature ( about 30 °C ) and a humidity 60% ( adding 60L water per 100 kg dry matter corn impurities that is meaning added 50L water for 90% dry matter of impurities which equivalent 60% humidity ) for 30 days of incubation period as Hassan and Tawffek (11) as follows: Calculate the amount of urea required to achieve 3.3% nitrogen ( 7.17 kg urea/ 100 Kg DM of impurities); Calculate the amount of water required to achieve 60% of humidity as DM basis of impurities, then, dissolve urea with water to prepare urea solution, put the impurities on clean nylon and spray prepared urea solution with manual mixing of impurities until homogeneity, then wrapped tightly to ensure the ammonia gas liberated from the decomposed urea does not come out.After 30 days, open the nylon with continuous mixing for drying and volatilization of the remaining ammonia gases.After drying, it was sampled for chemical analysis (Table 1) as AOAC (4) and collected in bags until they were used in experiment.Ingredients of concentrated feeds included barley, wheat bran, soybean meal, mineral and vitamins; wheat bran were replaced by treated and untreated corn impurities with urea as: 44:0%, 32:11%, 20:22%, 10:32% and 0:39%, all mixed to produce ten experimental treatments then sampled for analysis (Table 1) as AOAC (4).Concentrate was fed at 3% of body weight as DM basis, while alfalfa hay was provided ad libitum.

Experimental animals and management
Forty Awassi male lambs aged 4 -5 months with initial weight 27.45 ± 2.16 kg were randomly distributed to ten treatments to replace treated and untreated corn impurities with urea instead of wheat bran at levels: 0, 11, 22, 30 and 39 (%).Individual feeding was conducted for 70 days of experiment preceded by 14 days as adaptation period.All animals were provided clean water, vaccines and kept continuous veterinary supervision all experimental, concentrated feed was given at 3% of live body weight as DM basis, while alfalfa hay offered ad-libitum with remaining.Residual feeds were recorded to calculate daily intake and daily faecal were collected and weighted for five days to determine the digestibility of nutrients, there were weekly weighted for all replicate to monitor live weight changes.

Statistical analysis
All data were statistically analyzed using completely randomized design (CRD), factorial experiment 2 × 5, One-way ANOVA analysis was performed using statistical program (20) while Duncan's multiple range test was used to determine the significant differences (p<0.05) and (p<0.01)among treatments (7) using following formula:

RESULTS AND DISCUSSION Feed intake and digestibility
Results of table (2) indicated no significant effect of adding corn impurities on dry matter of nutrients and metabolizable energy ( MJ/ day) intakes, and linear increase of ash intake (P<0.01) with increasing corn impurities, and ether extract intake (g/ day) (P<0.01) for ureated corn impurities T8 compared with untreated T4, the insignificantly effects of daily feeds intake was a positive indicator to known good palatability of CI as well as wheat bran, while the increasing of ash intake with increasing corn impurities was due to increase ash content in agricultural residues 12.25% compared to 4.04% in wheat bran.Tawfeeq et al (25) referred to higher digestibility with increasing of DM intake, higher rumen flow rate with efficient fermented work when substituted hydroponics barley with barley grains to provide green fodder in tropical and subtropical countries that have few natural pastures due to lack of rain.The benefits of using by-products in feed are reducing environmental pollution and the cost of feed, recycling, integrated agricultural crops with animal husbandry, decreasing the competition between humans and animals for ingredients, which leads to increased productivity of land.
Hurley et al. (13) referred to increased animal production when they were given grass-clover compared to grass-only swards because of crude protein content.The increasing of processed feeds will make more industrial byproducts and co-products (26), so it's important to recycle by-products as much as possible.The effect of treated and untreated corn impurities instead of wheat bran on digestibility of dry matter and nutrients are shown in table (3).Significant increases in the DM digestibility and nutrients intake (P<0.05) with superiority for corn impurities treated with urea (ureated corn impurities, UCI) treatments comparison to untreated (CI).Ruminal digestibility controlling feed intake especially with low-energy diets (3), Crude fiber or structural carbohydrate is very important for the physiology ruminant's digestive system.So, corn impurities could be great especially with urea treatment, and the digestibility of metabolizable energy (%) increased with increasing impurities, the same way for crude protein digestibility (%), similar results was presented by Babale et al. ( 5) when replaced corn bran with corn cobs, and found better rumen characteristics, total bacteria count with 50% cobs relatively to better rumen ecosystem.The results of replacing treated and untreated corn impurities with urea instead of wheat bran showed no significant differences between treatments in initial and final weight (Table 4), while daily gain (g/day) and total gain (Kg) for the treatment 9 (T9) was significantly superior (P<0.05)comparison to other treatments.The non-significance of initial weight was due to the random distribution at the beginning of experiment that led to reduction in variation between treatments, while non-significance of final weight indicated to ability of substitution corn impurities instead of wheat bran without negative effects to growth performance, it is obviously that feeding ureated corn impurities 30% (T9) resulted in linear increases in weekly gain (kg) compared to T1 or control (figure 1), and the same results for final live weights (kg) of animals (figure 2).The results of feed efficiency (Table 5) indicated significant increases (P<0.05)especially when treating corn impurities with urea T9 compared to other treatments and accompanied by improvement energy and protein efficiency, Freitas et al. (10) evaluated the effect of corn, soybean hulls and wheat bran on performance of fattening steers and found that soybean hulls had better feed efficiency compared to wheat bran and referred that soybean hulls could completely replace corn to use as alternative source of carbohydrate in feeds, Ramos-Aviña et al. (19) said that high crude fiber in steam-flaked corn batter for daily gain and feed efficiency for fattening Holstein steers, Suárez et al. ( 22) said that roughages stimulate rumen development in earlier and could improve performance veal calves later in fattening, and Mollenhorst et al. (18) showed negative effects when increasing solid feeds in veal calves feeding.Therefore, it is important to follow the gradual provision of feed, change ingredients or increase the quantity, whether for small or large animals, to create adaptation within the rumen environment and the animal's body as a whole.In conclusion, it is possible to use corn impurities instead of wheat bran, preferably treated with urea.