Effects of Dietary Energy and Protein on Growth Performance and Carcass Quality of Broilers during Starter Phase

Lysolecithins improved growth performance, nutrient digestibility, immunity, and antioxidant ability in broiler chickens

OBJECTIVE

This study investigated the effects of dietary supplementation with lysolecithins (LPC) on growth performance, nutrient digestibility, blood profiles, immunity, and liver health in broiler chickens.

METHODS

A cohort of 240 one-day-old male Arbor Acres broilers of comparable weight was divided into four treatment groups, each comprising six replicates of 10 birds. The groups were defined as follows: positive control with recommended metabolizable energy (PC+ME), negative control with 90 kcal/kg reduced ME (NC+ME), PC supplemented with 300 mg/kg LPC (PC+LPC), and NC supplemented with 300 mg/kg LPC (NC+LPC).

RESULTS

LPC supplementation led to a statistically significant reduction in the feed conversion ratio (p = 0.05) and a decrease in the proportion of abdominal fat and the liver (p<0.05). Digestibility of dry matter was also enhanced (p<0.05). Malondialdehyde concentrations in the liver were significantly reduced by LPC (p<0.01), with a noteworthy interaction between energy levels and LPC affecting this reduction (p<0.05). Serum levels of interleukin-6 were reduced on day 21, and both endotoxin and interleukin-6 levels were lower on day 42. Notably, a significant interaction was observed between the energy levels and LPC on relative liver weight and endotoxin concentrations in the serum (p<0.05).

CONCLUSION

The study concluded that LPC positively affects growth performance, nutrient digestibility, immune response, and antioxidative capacity in broiler chickens, affirming its value as a beneficial feed additive in poultry nutrition.

Chromium propionate supplementation to energy- and protein-reduced diets reduces feed consumption but improves feed conversion ratio of yellow-feathered male broilers in the early period and improves meat quality

Growth performance and carcass traits may be retarded by low nutrient density diets. Organic chromium propionate (CrProp) can improve growth, carcass traits, and meat quality in farmed lambs, white broilers, and fish. Limited data regarding CrProp's impacts on yellow-feathered broilers are available. Eight hundred yellow-feathered male broilers (1-day old) were randomly allocated to 4 dietary groups and reared for 56 d. The trial was a 2 (dietary nutrient density) ×2 (CrProp) factorial arrangement with 4 diets: regular nutrient diet and low nutrient density (LND, reduction in metabolizable energy by 81 kcal and crude protein by 0.43%) diet supplemented with or without 200 mg/kg CrProp. Broilers were euthanized at d 56 after blood collection. The results indicated that the LND diet led to greater average daily feed intake (ADFI) from d 1 to 42 and feed conversion ratio (FCR) from d 22 to 42 (P < 0.05). Supplementation of CrProp improved body weight (BW) from d 1 to 56, average daily gain (ADG), and FCR during d 1 to 42 but reduced ADFI during d 1 to 21, as well as lowered abdominal fat percentage (P < 0.05). Supplementation with CrProp to regular and LND diets reduced ADFI but improved FCR from d 1 to 21 (P < 0.05). The LND diet lowered total antioxidant capacity (T-AOC) concentration and total superoxide dismutase (T-SOD) activity in the jejunal mucosa. CrProp elevated T-AOC levels and glutathione peroxidase activity (GSH-Px, P < 0.05). Dietary CrProp upregulated (P < 0.05) the expression of fatty acid transporter (FABP1) gene and peptide transporter (Pept1) gene. CrProp administration increased jejunal FABP1 expression and lowered cooking loss of breast meat (P < 0.05) in the LND group while reducing shear force (P = 0.009) of broilers treated by regular diet. In summary, CrProp administration to the LND diet can improve growth performance in the starter period and meat quality on d 56, possibly through upregulated nutrient transporter gene expression in the jejunum and enhanced antioxidant capability.

Varying apparent metabolizable energy concentrations and protease supplementation affected broiler performance and jejunal and ileal nutrient digestibility from 1 to 35 d of age

An experiment was conducted to evaluate the effects of varying AME concentrations and protease supplementation on broiler performance and jejunal and ileal nutrient digestibility from 1 to 35 d of age. Ross × Ross 308 male broilers (n = 1,008) were equally distributed into 48 floor pens and offered 1 of 6 dietary treatments (8 replicate pens/treatment). Dietary treatments consisted of a factorial arrangement with AME concentration (low-, moderate-, or high-AME) and supplemental protease (without or with) as the main factors. Birds and feed were weighed on 1, 15, 29, and 35 d of age to determine body BW, BW gain (BWG), feed intake (FI) and feed conversion ratio (FCR). At 15 and 29 d of age, jejunal and ileal digesta contents were collected to determine nutrient digestibility. From 1 to 15 d of age, broilers offered moderate-AME diets (P < 0.05) had 6.7, 7.1, 4.8% higher BW, BWG, FI, respectively, and a 2.1% lower FCR compared with those offered low-AME diets. Likewise, protease increased (P < 0.05) BW and BWG by 4.3 and 4.7%, respectively, and decreased (P < 0.05) FCR by 3.4%, compared with those offered the diets without protease. From 1 to 29 d of age, broilers offered high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) BW, BWG, and FI by 3.1, 3.2, and 4.2%, respectively, compared with the unsupplemented diets. From 1 to 35 d of age, broilers receiving high-AME diets had 2.9% lower (P < 0.05) FCR compared with those offered low-AME diets. Protease increased (P < 0.05) FCR by 1.0% compared with those offered unsupplemented diets. Jejunal (15 and 29 d of age) and ileal (29 d of age) starch digestibility and jejunal nitrogen digestibility (29 d of age) were lower (P < 0.05) in broilers offered high-AME diets compared with those offered low-AME diets. Both AME concentration and supplemental protease independently affected broiler performance, with responses being most apparent during early growth phases whereas digestibility measures were mainly influenced by AME concentration.

De-oiled soy lecithin positively influenced growth performance, nutrient digestibility, histological intestinal alteration, and antioxidant status in turkeys fed with low energy diets

1. The purpose of this research was to investigate the effects of supplementing an emulsifier (de-oiled soybean lecithin (DSL)) in a low metabolisable energy (ME) diet on growth performance, nutrient digestibility, carcase characteristics, intestinal morphology, blood metabolites, and antioxidant status in growing turkeys.2. A total of 480 one-day-old turkeys were assigned to one of four dietary treatments with of eight replicates of 15 birds each. Experimental treatments included a basal diet (BE) with commercially recommended levels of ME, a reduced energy diet (RE) with 0.42 MJ/kg reduction in dietary ME content, the RE diet + 1 g/kg DSL (DSL-1), and RE + 2 g/kg DSL (DSL-2).3. After 112 days, the body weight, average daily gain, and feed:gain in turkeys fed the supplemented for BE diets were better (P < 0.05) than in those fed RE, and those fed diet DSL-2 had the best performance. Although the RE diet decreased abdominal fat and relative liver weight (P < 0.05), compared to the BE diet, and supplementation with either level of DSL did not influence these variables.4. There were linear increases (P < 0.05) in fat digestibility, nitrogen-corrected apparent ME, and duodenal villus height, villus height/crypt depth ratio, and villus surface area in LE diet supplemented with DSL. From the jejunal morphology, crypt depth was decreased by DSL-supplemented diets (P < 0.05).5. Serum triglyceride, total cholesterol, and malondialdehyde concentrations were lower, whereas the serum superoxide dismutase activity was greater for the DSL-2 group compared to the BE and RE groups (P < 0.05).6. The findings suggested that, while low-ME diets impaired turkey growth performance, dietary supplementation of DSL could reverse such impacts of these diets. The DSL-supplemented diet at the inclusion level of 2 g/kg was advantageous over both BE and RE diets in terms of intestinal morphology, lipid profile, and antioxidant status in growing turkeys.

Effects of Dietary Energy Level on Performance, Plasma Parameters, and Central AMPK Levels in Stressed Broilers

This study aimed to characterize the effects of diets with different energy levels on the growth performance, plasma parameters, and central AMPK signaling pathway in broilers under dexamethasone (DEX)-induced stress. A total of 216 1-day-old male broiler chickens were allocated to groups fed with high (HED), National Research Council-recommended (control), or low (LED) energy diets. At 10 days old, chickens were treated with or without dexamethasone (DEX, 2 mg/kg body weight) for 3 consecutive days. HED increased broiler average daily gain (ADG) at 10 days old, compared with the LED (P < 0.05), while average daily feed intake (ADFI) and feed conversion rate (FCR) decreased as the dietary energy level increased (P < 0.05). Chickens fed a HED had higher total protein (TP) content, albumin (ALB), glucose (GLU), total cholesterol (TCHO), high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol, compared with the control group (P < 0.05). At 13 days old, DEX decreased ADG and increased FCR in broilers fed with different energy diets (P < 0.05). The DEX-HED group had a higher ADFI than non-DEX treated HED group chickens. In addition, TP, ALB, triglycerides (TG), TCHO, HDL, and LDL content levels in the DEX group were higher than those in the control group (P < 0.05). The uric acid (UA) content of the LED group was higher than that of the HED group (P < 0.05). Further, gene expression levels of liver kinase B1, AMP-activated protein kinase α1, neuropeptide Y, and GC receptor in the hypothalamus were increased in chickens treated with DEX (P < 0.05). There was a trend toward interaction between plasma TCHO and hypothalamic LKB1 expression (0.05 < P < 0.1). In conclusion, this study suggests that HED improves growth performance, plasma glucose and total cholesterol at 10 days old broilers, but had no significant effect on performance, plasma parameters, and central AMPK in stressed broilers.

Effects of diets with different energy and bile acids levels on growth performance and lipid metabolism in broilers

This experiment was conducted to evaluate the effects of bile acids (BAs) on the growth performance and lipid metabolism of broilers fed with different energy level diets. 480 one-day-old Arbor Acres broilers (45.01 ± 0.26 g) were allotted to a 2 × 2 factorial design with 2 levels of energy (basal or high-energy level) and 2 levels of BAs (with or without BAs supplementation), resulting in 4 groups of 8 replicates; the experiment lasted 42 d. High-energy diets decreased the feed/gain ratio (F/G) from 1 to 21 d (P < 0.05), and increased the liver index and abdominal fat percentage at 42 d (P < 0.05). The serum total triglyceride (TG) and high-density lipoprotein cholesterol at 42 d were increased by high-energy diets (P < 0.05), while the hepatic lipoprotein lipase (LPL) activity at 21 and 42 d was decreased (P < 0.05). BAs supplementation increased the body weight at 21 d and decreased the F/G during entire period (P < 0.05), as well as improved the carcass quality reflected by decreased abdominal fat percentage at 42 d and increased breast muscle percentage at 21 and 42 d (P < 0.05). The serum TG at 21 and 42 d were decreased by BAs (P < 0.05), and the hepatic LPL activity at 42 d was increased (P < 0.05). In addition, high-energy diets increased the expression of sterol regulatory element binding transcription factor 1, acetyl-CoA carboxylase, and fatty acid synthase (P < 0.05), while BAs diets decreased these genes expression (P < 0.05). Moreover, BAs supplementation also increased the expression of carnitine palmitoyltransferase 1 (P < 0.05), which was increased in high-energy groups (P < 0.05). In conclusion, BAs supplementation could increase growth performance, elevate carcass quality, and improve lipid metabolism in broilers.

Effects of reduced-protein diets supplemented with protease in broiler chickens under high stocking density

The effects of protease supplementation on productive performance and physiological responses were investigated in broiler chickens fed reduced crude-protein (low-CP) diets and reared under normal or high stocking densities (SD). Chicks were housed in pens with two stocking densities (≈10 birds/m2 or ≈15 birds/m2) and fed diets with either the recommended or reduced level of CP and metabolisable energy (ME) from 1 to 21 days. From 22 to 42 days, an equal number of birds from each dietary group was fed one of the following finisher diets: (1) recommended-CP and ME, (2) low-CP and recommended-ME or (3) low-CP and recommended-ME supplemented with protease. No interactions (P &gt; 0.05) were observed between diet and SD for feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Newcastle disease antibody titre, pododermatitis, caecal clostridia, Escherichia coli, lactobacilli, serum corticosterone or acute-phase proteins. Diet had no effect (P &gt; 0.05) on FI, WG or FCR during the finisher period nor on FI and WG during the overall (1–42 days) period. High SD resulted in lower FI (P &lt; 0.05) and Newcastle disease antibody titre (P &lt; 0.05) and higher FCR (P &lt; 0.05), pododermatitis incidence (P &lt; 0.05), caecal population of clostridia (P &lt; 0.05) and E. Coli (P &lt; 0.05), and acute-phase protein and corticosterone concentrations than did normal SD. In conclusion, the supplementation of protease to a low-CP diet during the finisher period had no effect on the performance and immunity of overcrowded broiler chickens. Regardless of dietary CP and protease supplementation, a high SD negatively affected the growth performance, immunity, caecal microflora and welfare of the broiler chickens.

Effect of dietary energy and protein content on growth and carcass traits of Pekin ducks

A study was conducted to determine the influence of dietary energy and protein concentrations on growth performance and carcass traits of Pekin ducks from 15 to 35 d of age. In experiment 1, 14-d-old ducks were randomly assigned to 3 dietary metabolizable energy (11.8, 12.8, and 13.8 MJ/kg) and 3 crude protein concentrations (15, 17, and 19%) in a 3 × 3 factorial arrangement (6 replicate pens; 66 ducks/pen). Carcass characteristics were evaluated on d 28, 32, and 35. In Experiment 2, 15-d-old ducks (6 replicate cages; 6 ducks/cage) were randomly allotted to the 9 diets that were remixed with 0.5% chromic oxide. Excreta were collected from d 17 to 19, and ileal digesta was collected on d 19 to determine AME_n and amino acid digestibility. In Experiment 1, there were interactions (P < 0.05) between dietary metabolizable energy and crude protein (CP) on body weight (BW) gain and feed intake, wherein BW gain increased more to increasing dietary CP as dietary metabolizable energy increased. However, feed intake was only influenced by dietary crude protein at 11.8 MJ ME/kg and not 12.8 or 13.8 MJ/kg. As dietary CP increased from 15 to 19%, breast meat yield increased by 10.8% on d 35 (P < 0.01). Conversely, increasing metabolizable energy from 11.8 to 13.8 MJ/kg increased dressing percentage, breast skin, and subcutaneous fat, but decreased breast meat yield (% but not weight) on d 35 (P < 0.01). In Experiment 2, the determined AME_n for diets formulated to contain 11.8, 12.8, or 13.8 MJ ME/kg were 11.66, 12.68, and 13.75 MJ/kg, respectively; determined standardized ileal digestible Lys was 0.95, 1.00, and 1.21% for diets formulated to contain 15, 17, or 19% crude protein, respectively. The best body weight gain and feed conversion ratio was obtained when ducks were fed a high dietary AME_n (13.75 MJ/kg) and high CP (19%, 1.21% SID Lys). These results provide a framework for subsequent modeling of amino acid and energy inputs and the corresponding outputs of growth performance and carcass components.