Effect of Feeding Wet Feed or Wet Feed Fermented by Bacillus licheniformis on Growth Performance, Histopathology and Growth and Lipid Metabolism Marker Genes in Broiler Chickens

Abstract

The present study evaluated the effect of three feeding methods (dry feed, wet feed or wet feed fermented with Bacillus licheniformis) on the growth performance, intestinal histomorphometry and gene expression of the lipid metabolism- and growth-related genes of broiler chickens. A total of 360 one-day-old Cobb-500 broiler chicks were randomly allotted into three groups containing four replicates with 30 birds each. The first group (control) was fed a dry mash basal diet. The second and third groups were fed wet feed and fermented wet feed. The final body weight and weight gain were reduced (p < 0.01) in the wet feed group, while they did not differ between the fermented wet feed and dry feed groups. Feed intake was not altered, and feeding on wet feed significantly (p < 0.01) increased the feed-to-gain ratio compared to the remaining groups. No differences between the three feeding methods in carcass characteristics, blood biochemistry and nutrient digestibility were observed except for crude protein digestibility, which was increased (p < 0.01) in the fermented wet feed group. Duodenal and ileal villi heights were elevated in birds fed fermented wet feeds, while crypt depth was not altered. The expression fold of IGF-1, GH and m-TOR genes in the pectoral muscle of birds fed wet feed was decreased (p < 0.05), while myostatin gene expression was elevated. Feeding on wet feed reduced the hepatic gene expression of PPARγ and increased that of FAS. In conclusion, wet feed negatively affected the broiler chickens' efficiency under heat stress; however, fermenting the wet feed with Bacillus licheniformis improved feed utilization and birds' performance compared to the dry feed group.

Keywords: broilers; dry feed; fermented wet feed; gene expression; intestinal morphology; performance.

Figure 1

Representative photomicrograph of the duodenum of a broiler of the dry feed (A), wet feed (B) and fermented wet feed (C) groups showing the simple columnar epithelium of the tunica mucosa (1), connective tissue core of intestinal villi (2), intestinal glands (3), tunica muscularis (4) and tunica serosa (5). H&E, bar = 100 µm. (n = 8).

Figure 2

Representative photomicrograph of the ileum of a broiler of the dry feed (A), wet feed (B) and fermented wet feed (C) groups showing the simple columnar epithelium of the tunica mucosa (1), connective tissue core of intestinal villi (2), tunica muscularis (3) and tunica serosa (4). H&E, bar = 100 µm. (n = 8).

Figure 3

Representative photomicrograph of the cecum of a broiler of the dry feed (A), wet feed (B) and fermented wet feed (C) groups showing the simple columnar epithelium of the tunica mucosa (1), lamina propria with extensive deposits of lymphatic cells (2), tunica muscularis (3) and tunica serosa (4). H&E, bar = 100 µm. (n = 8).

Figure 4

Duodenal and ileal histomorphometry of 35-day-old broiler chickens as affected by dry, wet and fermented wet feeds. Data are presented as the mean values with their standard errors. (*) indicates (p < 0.05), (**) indicates (p < 0.01). Asterisk located above the columns indicates significance between different treated groups and the fermented wet feed group. (n = 8).

Figure 5

Reverse transcription-polymerase chain reaction (RT-PCR) validation of hepatic lipoprotein lipase (LPL), peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid synthase (FAS), and muscular myostatin, myogenin, mammalian target of rapamycin (mTOR), insulin growth factor 1 (IGF1) and growth hormone (GH) of 35-day-old broiler chickens as affected by dry, wet and fermented wet feeds. Data are presented as the mean values with their standard errors. (≠) indicates no significant changes, (*) indicates (p < 0.05). Asterisk located above the columns indicates significance between different treated groups and the wet feed group. (n = 8).