Influence of barley inclusion method and protease supplementation on growth performance, nutrient utilisation, and gastrointestinal tract development in broiler starters

Abstract

The influence of the method of barley inclusion (fine, coarse and whole barley) in a wheat-based diet and protease supplementation (0 and 0.20 g/kg) on growth performance, nutrient utilisation and gastrointestinal tract development of broilers (d 1 to 21) was evaluated in a 3 × 2 factorial arrangement. Whole barley (WB) grains were ground in a hammer mill to pass through the screen sizes of 2.5 and 8.0 mm to achieve fine (FB) and coarse (CB) barley particle sizes, respectively. A total of 288, one-day-old male broilers were allotted to 36 cages (6 cages/treatment; 8 birds/cage). There was no significant ( P > 0.05) interaction between barley inclusion method and protease for any growth performance or nutrient utilisation parameters. Birds fed diets containing CB and WB showed higher ( P < 0.05) weight gain, and digestibility of dry matter, nitrogen, calcium, gross energy, and ileal digestible energy compared to those fed FB diets. Compared to the birds fed FB diets, feed per gain was lower ( P < 0.05) in birds fed diets made of WB. Fat digestibility of the birds fed CB was higher ( P < 0.05) than those fed FB and WB birds. Compared to FB and CB diets, inclusion of WB resulted in heavier ( P < 0.05) gizzards but reduced ( P < 0.05) gizzard pH. Supplemental protease, however, had no effects ( P > 0.05) on growth performance and nutrient utilisation, most likely due to the well balanced digestible amino acids and high inherent digestibility of protein in the basal diet, and/or the presence of exogenous carbohydrase and phytase. In conclusion, the present results showed that the inclusion of coarsely ground and whole barley in a wheat-based diet can enhance nutrient and energy utilisation and is beneficial to the growth performance of young broilers.

Supplemental Enzyme and Probiotics on the Growth Performance and Nutrient Digestibility of Broilers Fed with a Newly Harvested Corn Diet

“…Interestingly, our research shows that there were no significant differences in broilers BW and BWG and nutrient digestibility between supplementation of enzymes and probiotics, compared with the newly harvested corn diet group. This is consistent with the findings of Hussein et al (2020) [ 34 ], Al-Khalaifa et al (2019) [ 18 ], and Tari et al (2022) [ 35 ]. This result may be related to the good balance of digestible amino acids and the high inherent protein digestibility in the basal diet and complex changes in digestive enzyme activities.…”

Barley, an Undervalued Cereal for Poultry Diets: Limitations and Opportunities

“…However, Perera et al [ 149 ] reported that starch digestibility in broilers fed barley-based diets was not influenced by barley particle size. In agreement, Tari et al [ 151 ] reported no influence of the method of barley inclusion (fine, coarse and WB) in wheat-based diets on starch utilisation. Enhanced starch digestibility may also be attributed to mechanisms facilitated by well-developed gizzards.…”

“…Enhanced starch digestibility may also be attributed to mechanisms facilitated by well-developed gizzards. However, no impact on the starch digestibility was reported despite functional gizzards in birds fed coarse [ 149 ] and WB [ 151 ]. On the other hand, a recent study [ 152 ] reported an enhanced starch digestibility in response to increasing the WB inclusions from 0 to 141 and 282 by 3.6 and 5.7%, respectively, despite the lack of impact on gizzard size.…”

“…A 19% increase in the relative weight of gizzard was reported in response to the increasing barley particle size from fine to coarse (2.0 vs. 8.00 mm [ 149 ]). Tari et al [ 151 ] compared different methods (fine, coarse and WB) of barley inclusion (283 g/kg) in a wheat-based diet and reported reduced weights of crop, proventriculus, jejunum and ileum, but greater gizzard weights in WB than fine and coarse-barley diets. In contrast, a recent study in our laboratory [ 152 ] reported no impact of WB inclusion at 141 and 282 g/kg in barley-based diets on gizzard development.…”

“…Moreover, coarse grinding increased the CAID of DM, N and fat by 3.1, 3.2 and 4.3%, respectively, compared to those fed fine-barley diets. Tari et al [ 151 ] evaluated the influence of the method of barley inclusion (fine, coarse and WB) in a wheat-based diet and reported that birds fed coarse and WB diets had higher WG than those fed fine barley diets by an average of 36.5 g/bird at 21 d of age, attributed to the increases in digestibility of nutrients. These findings are suggestive of the potential to enhance the feeding value of barley in poultry diets through strategic manipulation of feed processing practices.…”