R1, ration 1; R2, ration 2; R3, Ration 3.

Feeding procedures

The growing lambs were fed CFM and clover hay twice daily to cover their total requirements of sheep according to NRC (1985) and animals were fed in groups. Water was allowed freely all the day round. Orts were collected just before offering the next day feed. Lambs were weighed every two weeks before morning feeding after 15 h of fasting. Rations were adjusted every two weeks according to body weight changes (Khattab et al., 2011). Body weight gain was recorded and daily feed intake was calculated. Dry matter (DM), total digestible nutrients (TDN) and digestible crude protein (DCP) intake were calculated. Feed conversion ratio was calculated as follow (intake g/daily gain g) for DM, TDN and DCP.

Digestion trials

Nutrients digestibility were determined by the acid insoluble ash (AIA) technique as described by Van Keulen and Young (1977) to determine the nutrients digestibility and the nutritive values of the experimental rations. In these trials the experimental rations consisted of 60 % CFM and 40% clover hay.

Chemical analyses

Dried feed, orts, feces samples were ground through a Wiley mill (Arthur H. Thomas, Philadelphia, PA, USA) using a 1 mm screen. Samples were analyzed for DM (#930.15), N (#954.01), ash (#942.05) and ether extract (EE; #920.39), according to AOAC (1997), while fiber fractionations (i.e. NDF and acid detergent fiber, ADF) were completed according to Van Soest et al. (1991). Nitrogen free extract was calculated by difference.

Rumen liquor sampling

Rumen liquor samples were taken just before morning feeding, and four hours post feeding. Samples of rumen liquor were strained through two layers of cheesecloth and its pH was immediately measured after collection. The pH value of rumen liquor samples was determined using pH meter. Quantitative analysis of ammonia concentration was carried out by a modified Nessler’s method modified by Szumacher-Strabel et al. (2002).

Blood parameters

At the end of the digestion trials blood samples were taken from 5 animals. Blood plasma parameters were analyzed using specific kits obtained from Stanbio Laboratory, Boerne, Texas, USA; for total protein and creatinine as described by Tietz (1986) and Tietz et al. (1990), albumin was determined according to Doumas et al. (1971), blood plasma urea was determined according to Patton and Grouch (1977). Alanine aminotransferase (ALT) and aspartate aminotransfearse (AST) activities were colorimetrically determined according to AST and ALT kits (Quimica Clinica Aplicada S.A., Spain) based on reaction of Young (1997). Glucose was executed by using kits of Stanbio Laboratory Inc, procedure No. 1070. (San Antonio, Texas, USA). Total lipids, triglycerides and total cholesterol were quantified by using a calorimetric method by using kits of the Bio diagnostic company.

Meat sampling

After the end of the growth trial, four animals from each group were slaughtered in a slaughter. Meat chemical analysis was performed using Food Scan™ Pro meat analyzer (Foss Analytical A/S, Model 78810, Denmark). According to the manufacturer’s instructions about 50 - 100 gm of raw meat (obtained from the 9th rib) were minced and put in the meat analyzer cup. The cup was inserted into the meat analyzer for scanning sample with infra-red to determine the chemical components.

Statistical analysis

Data were analyzed using the general linear model procedure of SAS (2001, Ver.8.02, SAS Institute Inc., Cary, NC, USA). One way ANOVA procedure used to analyze data according to the next model; Yij=µ+Tij+eij, were: µ is overall mean of Yij; Tij is treatment effect; the eij is experimental error. Differences among means were separated according to Duncan New Multiple Range Test (Duncan, 1955).

Results and Discussion

Data of chemical composition and fiber fractions of the experimental ingredients and the experimental rations are shown in Table II. Analysis of yellow corn and wheat bran were used in this study were much closed to their standard reported by CLFF (2001) for feedstuffs used in animal nutrition in Egypt. Chemical analysis of BBP revealed that crude protein content was close to that of wheat bran but was more than that of yellow corn by 5.57% units. Ether extract of BBP (13.19%) was greater than yellow corn and wheat bran, being 5.74 and 3.64 %, respectively. However, nitrogen free extract content of corn was the highest (81.65%) followed by BBP (68.34%) and wheat bran (55.93%). Fiber fractions of the experimental feed ingredients cleared that wheat bran had higher values of NDF, ADF, ADL, cellulose and hemi-cellulose compared to corn and BBP. No differences were observed among the experimental rations in chemical composition except EE, CF and CP with R3. Previous studies showed that BBP had a wide variation in its chemical composition especially in ether extract. Such variation makes it difficult to compare these values to those obtained by other researchers. The differences in bread by-product or bakery waste could be related to the bread source, origin, components, and processing method. Therefore, it is recommended to analyze the nutrient content of bread byproduct before inclusion in the ruminant diets (França et al., 2012; Guiroy et al., 2000). Champe and Church (1980), studied the use of bakery waste in sheep diet and noticed the following values of 8.5 and 10.4% for CP and EE contents, respectively.

ADF, acid detergent fiber; ADL, acid detergent lignin; BBP, bakery by-products; CF, crude fiber; CP, crude protein; DM, dry matter; EE, ether extract; NDF, neutral detergent fiber; NFE, nitrogen free extract; OM, organic matter; WB, wheat bran; YC, yellow corn.

Dale (1990), Saleh et al. (1996), Guiroy et al. (2000), Al-Tulaihan et al. (2004), Carneiro et al. (2006) and Kwak and Kang (2006) reported different values of EE (11.10, 11, 1.32 and 17.70 %), and CP (10.6, 12.5, 12.2, 9.9%). Arosemena et al. (1995) evaluated the chemical composition of bakery waste from different areas and showed variations of 4.46 to 11.70% in EE contents, and from 11.9 to 13.3% in CP contents.

Means in the same row with different superscript are significantly different (P<0.05). For abbreviations, see Table II.

Results of nutrients digestibility and nutritive values of the experimental rations are shown in Table III. No significant differences were recorded among the experimental rations except digestion coefficient of crude protein and digestible crude protein. These results may be partly due to the similarity of chemical analysis of the experimental rations except crude protein content. The same trend was observed by França et al. (2012) when they fed sheep bakery waste and corn meal at varying proportions (0, 25, 50, 75, and 100%). The nutritive values as total digestible nutrients in the current study were higher than those obtained by Waller (2010) and França et al. (2012). In the same context, Champe and Church (1980) determined nutrients digestibility of diets with 0, 30 and 60% of corn replacement by bakery by-products, and observed an improvement in DM digestibility being; 68.3, 73.5 and 78.3% for the three replacement levels, respectively. Also, Carneiro et al. (2006) found no effect of substituting up to 80% of the corn by bakery waste on DM digestibility by sheep. As well as, Haddad and Ereifej (2004) showed that digestibility coefficients of DM, OM, and NDF were not affected with increasing bakery by-products levels of 10, 20, and 30 % DM, in goat kids ration.

Means in the same row with different superscript are significantly different (P<0.05).

Data in Table IV shows the inclusion of BBP at both levels in concentrate portion had no effect (P>0.05) on pH values or ruminal ammonia concentration either before or after 4 hours of feeding. Smith et al. (1972) found that ruminal pH value ranged from 6.0 to 6.8 and that provide maximum activity of cellulolytic organisms and that the inclusion of bakery waste in diet did not negatively affect the rate of microbial growth. Numerically lower value of ruminal ammonia concentration (18.87) was recorded for R3 compared with other rations. This reduction in ruminal NH3-N concentration may be related to the increase in energy availability for microbial protein synthesis, provided by the bakery waste inclusion in the diet (França et al., 2012). Carvalho et al. (1997) reported that the reduction in ruminal NH3-N concentration can be explained by the increase in energy availability in the rumen, allowing higher use of ammonia for microbial growth, with consequent reduction in ammonia loss due to synchronization in the carbohydrates and protein degradation. Similarly, Mehrez et al. (1977) found that the maximum rate of fermentation in the rumen is obtained when the NH3-N concentration reaches values between 19 and 23 mg/dl rumen fluid. On contrary, Van Soest (1994) reported the optimal level of 10 mg NH3/dl, a value lower than the concentration of NH3-N obtained with the proportion of 100% of bakery waste. However, this should not be considered a fixed number, considering that the ability of bacteria to use ammonia and to synthesize protein depends on the roughage: concentrate ratio of the diet.

Means in the same row with different superscript are significantly different (P<0.05). ALT, alanine aminotransferase; AST, aspartate aminotransferase.

Data of blood parameters in Table V showed significant effects of the experimental rations on total proteins, albumin, globulin and blood glucose. Total protein recorded the highest value (7.05g/dl) with R3 compared with R1 and R2. This may be due to crude protein content, digestion coefficients and digestible crude protein in R3 (15.41, 64.97, and 10.01%, respectively). Blood glucose concentration was higher in R1 (51) compared with R2 and R3 (46.5 for both). No significant differences were observed among the different groups in cholesterol, triglycerides, urea, creatinin, ALT and AST. Generally, all blood parameters were in normal range of healthy sheep. These results agreed Ghoneem and Mahmoud (2014).

Results of growth performance in Table VI showed insignificant effect of including bakery by-products at both levels in rations on final, total and average daily gain of the experimental animals. Although, R3 recorded insignificant increase in growth rate by 9 g daily compared to the control which will affect on the total weight especially in the case of feeding in large scale. Results of meat analysis revealed that no significant differences were observed among experimental groups. Ash content in animal meat fed R3 (1.96%) was lower compared to other animals. These results may be a reflection of the nutritive values of the experimental rations. These results were compatible with Guiroy et al. (2000) when bakery by-products substituted up to 75% of whole shelled corn in a growing finishing beef feedlot ration without reducing meat quality or feedlot performance. Similar results were reported by Haddad and Ereifej (2004) when barley grain were replaced by bakery by-products in fattening kid’s diets and observed that replacement of barley grain up to 20% of the diet DM had no effect on animal performance.

Means in the same row with different superscript are significantly different (P<0.05).

Results in Table VII showed that both levels of replacement of corn grain and wheat bran by BBP had no significant (p>0.05) on dry matter and total digestible nutrients intake among the experiment rations. This finding was matched the results of Obeidat et al. (2012). Also, Afzalzadeh et al. (2007) observed no significant differences in DM intake when fattening Zandi lambs fed diets containing bakery waste at levels of 6, 12.5, and 25% DM compared to control. While, digestible crude protein recorded lower value (97 g) with R3 compared with other rations. This data was in agreement with Hindiyeh et al. (2011) noticed protein intake decreased in Awassi lambs fed diets contained various levels of bakery waste. Also, Champe and Church (1980) stated that feed intake was lower in sheep fed dry bakery product at level of 40% DM than sheep fed control diet. Similarly, Haddad and Ereifej (2004) found that DM and CP intakes decreased in goat kids fed BBP at level of 30% DM versus kids fed lower levels of BBP (0, 10, or 20% DM). It was expected that feeding highly fermentable carbohydrates such as BBP may reduce the feed intake and cause acidosis (Morgante, 2002). However, herein there was no reduction in feed intake was observed in all diets. In the current study, no signs of clinical acidosis were observed among lambs. Also, subclinical cases are also unexpected as no differences in intake were identified.

Feed conversion recorded the best values with R3 especially with DCP (0.51) compared with R2 and R1. There was an improvement in economic efficiency by 5% and 10% with R2 and R3 compared with control ration R1 (Table VII). These results are in consistencies with Hindiyeh et al. (2011) and Obeidat et al. (2012).

Means in the same row with different superscript are significantly different (P<0.05). Prices are in Egyptian Pounds, (LE); R1, 2 LE/kg; R2, 1.95 LE/kg; R3, 1.90 LE/kg; live weight for Barki lambs, 42 LE/kg.

Conclusion

Similarity in the performance of growing lambs (nutrient intakes and digestibility, body weight changes and meat analysis), leads to the conclusion that bakery by-product could be replace up to 60% (DM basis) of the corn grain and wheat bran in growing lambs concentrate feed mixtures.

Conflict of interest statement

The authors have declared no conflict of interest.

References