M. Frikha

Productive Performance and Egg Quality of Brown Egg-Laying Hens in the Late Phase of Production as Influenced by Level and Source of Calcium in the Diet

A total of 1,152 Lohmann Brown laying hens were used to study the influence of level (3.5 and 4.0%) and source (coded FIN, COA, and OYS) of Ca in the diet on productive performance and egg quality from 58 to 73 wk of age. The FIN diet contained all the Ca carbonate as fine limestone (LIM). In the COA and OYS diets, 40% of the fine LIM was substituted with either coarse LIM or oyster shell. Each treatment was replicated 8 times (24 hens). Productive performance and egg quality traits were recorded every 4 wk, and tibia characteristics and shell quality traits were determined at 73 wk of age. An increase in Ca intake from 4.08 to 4.64 g/hen per day improved egg production (71.2 vs. 74.9%; P < 0.001), egg mass (49.0 vs. 51.4 g; P < 0.05), and feed conversion ratio (2.43 vs. 2.30 kg of feed/kg of egg; P < 0.001). In addition, an increase in Ca intake improved shell weight (9.98 vs. 10.20%; P < 0.05), shell thickness (0.342 vs. 0.351 mm; P < 0.01), and shell density (82.0 vs. 83.8 mg/cm2; P < 0.001). Calcium source had no effect on productive performance, tibia characteristics, or egg quality except for shell density, which was greater for hens fed COA than for hens fed FIN, with hens fed OYS being intermediate (81.9 vs. 84.0 vs. 82.7 mg/cm2, respectively; P < 0.05). It was concluded that Brown egg-laying hens in the late phase of production require more than 3.5% Ca in the diet (4.08 g of Ca/hen per day) and that the substitution of 40% of fine LIM with COA or OYS does not affect productive performance and has little impact on shell quality and tibia characteristics.

Effect of main cereal of the diet and particle size of the cereal on productive performance and egg quality of brown egg-laying hens in early phase of production

A total of 960 Lohmann Brown laying hens were used to study the effects of the main cereal of the diet and geometric mean diameter (GMD) of the cereal on productive performance and egg quality from 20 to 48 wk of age. The experiment was a completely randomized design with 6 treatments arranged factorially with 2 cereals (dent corn vs. durum wheat) and 3 GMD of the cereal (hammer-milled to pass through 6-, 8-, or 10-mm screens). Each treatment was replicated 8 times (20 hens per replicate). All diets were formulated to be isonutritive and contained 50% of either corn or wheat. Productive traits were recorded every 4 wk and egg quality was measured at 48 wk of age. The only significant effect detected was for feed intake (P < 0.05) that was greater for hens fed coarse-ground cereals (10-mm screen) than for hens fed medium and fine-ground cereals (8- or 6-mm screen). None of the egg quality parameters studied were influenced by dietary treatment. We conclude that neither type of cereal nor GMD affected productive performance or egg quality of young brown hens, except for feed intake that increased with the coarser particle size.

Effects of energy concentration of the diet on productive performance and egg quality of brown egg-laying hens differing in initial body weight

The influence of AME(n) concentration of the diet on productive performance and egg quality traits was studied in Hy-Line brown egg-laying hens differing in initial BW from 24 to 59 wk of age. Eight treatments were arranged factorially with 4 diets varying in energy content (2,650, 2,750, 2,850, and 2,950 kcal of AME(n)/kg) and 2 initial BW of the hens (1,733 vs. 1,606 g). Each treatment was replicated 5 times (13 hens per replicate), and all diets had similar nutrient content per unit of energy. No interactions between energy content of the diet and initial BW of the hens were detected for any trait. An increase in energy concentration of the diet increased (linear, P < 0.05; quadratic P < 0.05) egg production, egg mass, energy efficiency (kcal of AME(n)/g of egg), and BW gain (P < 0.05) but decreased ADFI (linear, P < 0.001) and feed conversion ratio per kilogram of eggs (linear, P < 0.01; quadratic P < 0.01). An increase in energy content of the diet reduced Haugh units and the proportion of shell in the egg (P < 0.01). Feed intake (114.6 vs. 111.1 g/hen per day), AME(n) intake (321 vs. 311 kcal/hen per day), egg weight (64.2 vs. 63.0 g), and egg mass (58.5 vs. 57.0 g) were higher for the heavier than for the lighter hens (P < 0.01), but feed conversion ratio per kilogram of eggs and energy efficiency were not affected. Eggs from the heavier hens had a higher proportion of yolk and lower proportion of albumen (P < 0.01) and shell (P < 0.05) than eggs from the lighter hens. Consequently, the yolk-to-albumen ratio was higher (P < 0.001) for the heavier hens. It is concluded that brown egg-laying hens respond with increases in egg production and egg mass to increases in AME(n) concentration of the diet up to 2,850 kcal/kg. Heavy hens had higher feed intake and produced heavier eggs and more egg mass than light hens. However, feed and energy efficiency were better for the lighter hens.

Influence of the main cereal and feed form of the diet on performance and digestive tract traits of brown-egg laying pullets

The influence of the main cereal and feed form of the diet on performance and digestive tract traits was studied in 576 brown-egg laying pullets from 1 to 120 d of age. From 1 to 45 d of age, 4 diets arranged factorially with 2 cereals (corn vs. wheat) and 2 feed forms (mash vs. pellets) were used. Each treatment was replicated 6 times (24 pullets per replicate). From 46 to 120 d of age, all diets were offered in mash form and the only difference among diets was the cereal used. Cumulatively, pullets fed the corn diets had higher BW gain (P < 0.05) but similar feed conversion ratio as pullets fed the wheat diets. From 1 to 45 d of age, pullets fed pellets consumed more feed (P < 0.001) and had higher BW gain (P < 0.001) than those fed mash. Most of the beneficial effects of pelleting on productive performance were still evident at 120 d of age. At 45 d of age, gizzard weight (g/kg of BW) was higher (P < 0.01) in pullets fed corn than in pullets fed wheat diets. Feeding pellets reduced the relative weight of the digestive tract and the gizzard (P < 0.001) as well as the length (cm/kg of BW) of the small intestine (P < 0.01) at both ages. The pH of gizzard contents at 120 d of age was not affected by cereal but was lower in pullets that were fed mash from 1 to 45 d of age (P < 0.01). We conclude that wheat can be used in substitution of corn in pullet diets with only a slight reduction in BW gain and that feeding pellets from 1 to 45 d of age increased BW gain and pH of the gizzard and reduced the relative weight of the gizzard and the length of the gastrointestinal tract at 120 d of age.

Effects of the main cereal and type of fat of the diet on productive performance and egg quality of brown-egg laying hens from 22 to 54 weeks of age

The influence of the main cereal and type of supplemental fat in the diet on productive performance and egg quality of the eggs was studied in 756 brown-egg laying hens from 22 to 54 wk of age. The experiment was conducted as a completely randomized design with 9 treatments arranged factorially, with 3 cereals (dented corn, soft wheat, and barley) and 3 types of fat (soy oil, acidulated vegetable soapstocks, and lard). Each treatment was replicated 4 times (21 hens/replicate). All diets were formulated to have similar nutrient content, except for linoleic acid, which ranged from 0.8 to 3.4% depending on the combination of cereal and fat source used. This approach allows for the estimation of the minimum level of linoleic acid in the diets that maximizes egg weight. Productive performance and egg-quality traits were recorded every 28 d, and the BW of the hens was measured individually at the beginning and at the end of the experiment. No significant interactions between main factors were detected for any of the variables studied. Egg production, egg weight, and egg mass were not affected by dietary treatment. Body weight gain was higher (P < 0.05) for hens fed corn or wheat than for hens fed barley, and also higher for hens fed lard than for hens fed soy oil or acidulated vegetable soapstocks. Egg quality was not influenced by dietary treatment, except for yolk color, which was greater (P < 0.001) for hens fed corn than for hens fed wheat or barley, and greater for hens fed lard than for hens fed soy oil or acidulated vegetable soapstocks. We concluded that brown-egg laying hens do not need more than 1.0% of linoleic acid in their diet (1.16 g/hen per d) to maximize egg production and egg size. The 3 cereals and the 3 fat sources tested can replace each other in the diet provided that the linoleic acid requirements to maximize egg size are met.

Influence of feed form and source of soybean meal on growth performance, nutrient retention, and digestive organ size of broilers. 2. Battery study

Two experiments were conducted to determine the apparent ileal digestibility (AID) of the amino acids (AA) of 4 commercial soybean meals (SBM) from the United States (USA-1, 48.1% CP and USA-2, 46.2% CP), Brazil (BRA, 47.6% CP), and Argentina (ARG, 46.3% CP) and the effects of the inclusion of these SBM in diets in mash, crumble, or pellet form on growth performance, total tract apparent retention of nutrients, and digestive organ size in broilers reared in cages from 1 to 25 d of age. In experiment 1, the AID of Lys was higher (P < 0.05) for the USA-2 than for the BRA SBM, with the SBM from USA-1 and ARG being intermediate. In experiment 2, 12 diets were arranged as a 3 × 4 factorial with 3 feed forms (mash, crumbles, and pellets) and the 4 sources of SBM used in experiment 1. The feeds were isonutritive and the AID of the AA of the SBM obtained in experiment 1 was used for diet formulation. Broilers fed mash had lower (P < 0.001) ADFI and ADG and poorer (P < 0.001) feed-to-gain ratio than broilers fed crumbles or pellets but source of SBM did not affect growth performance. Nitrogen retention was higher (P < 0.01) in birds fed mash than in birds fed crumbles or pellets at all ages. The total tract apparent retention of nutrients was lower (P < 0.05) for the BRA and ARG SBM diets than for the USA-1 and USA-2 SBM diets. Gizzard empty relative weight (% BW) was higher and gizzard pH lower for broilers fed mash than for broilers fed crumbles or pellets (P < 0.001). The results indicate that crumbling or pelleting of the diets improved growth performance of broilers from 1 to 25 d of age. Diets formulated with analyzed rather than calculated AID of AA of the SBM sources resulted in similar broiler performance.

Influence of source of soybean meal and lysine content of the diet on performance and total tract apparent retention of nutrients in broilers from 1 to 36 days of age

The influence of soybean meal (SBM) source and total Lys content of the diet on performance and total tract apparent retention of nutrients was evaluated in broilers from 1 to 36 d of age. There were 6 treatments arranged factorially with 2 sources of SBM [regular SBM with 46.3% CP (R-SBM) and high-protein SBM with 48.6% CP (HP-SBM)] and 3 Lys:AME(n) ratios (Lys:ME; 380, 415, and 450 mg of total Lys:1,000 kcal of AME(n) from 1 to 21 d; and 312, 338, and 364 mg of total Lys:1,000 kcal of AME(n) from 22 to 36 d of age). From 1 to 36 d of age, broilers fed the HP-SBM diets had higher ADG and better feed:gain ratio (F:G) than broilers fed the R-SBM diets (P < or = 0.001). Both ADG and F:G improved (P < or = 0.05) with increases in the Lys:ME ratio. From 1 to 21 d of age, ADG and F:G (P < or = 0.001) were improved when the Lys:ME ratio increased and the benefits were more pronounced with the diets based on R-SBM. From 22 to 36 d of age, increasing the Lys:ME ratio from 312 to 338 increased ADG (P < or = 0.05) and F:G (P < or = 0.01), but no further improvements were observed when the ratio was increased to 364. The total tract apparent retention of DM and gross energy of the diets were higher (P < or = 0.05) for the HP-SBM than for the R-SBM diets. An increase in the Lys:ME ratio reduced organic matter and N retention (P < or = 0.05). The improvements in growth performance and nutrient retention observed in broilers fed the HP-SBM diets with respect to those fed the R-SBM are consistent with a better availability of nutrients of the high-protein meal. In addition, the results indicate that Lys requirements of broilers are at least, 30, 20, and 8% higher from 1 to 10, 10 to 21, and 21 to 36 d of age, respectively, than current NRC recommendations.

Ileal digestibility of amino acids of unheated and autoclaved pea protein concentrate in broilers

The effects of autoclaving 2 varieties of micronized (fine grinding) pea protein concentrate (PPC) on the ileal digestibility (ID) of CP and amino acids (AA) were studied in broilers. There was a control diet based on fermented soybean meal (FSBM) and 4 extra diets in which the FSBM was substituted on a CP basis by PPC from 2 different pea cultivars (PPC-1 and PPC-2), either unheated or autoclaved. Chicks were fed a common diet from 1 to 17 d of age and, then, their respective experimental diets from 18 to 21 d of age. Each treatment was replicated 6 times. Autoclaving reduced trypsin inhibitor activity (TIA) but had little effect on the saponin content of the PPC. The apparent ID (AID) of CP was similar for the FSBM and the unheated PPC and lower for both than for the autoclaved PPC. Autoclaving improved (P < 0.001) the AID of CP (87.6 vs. 82.2%) and most indispensable AA (e.g., 92.1 vs. 88.8% for Lys and 83.6 vs. 76.5% for Thr) of the PPC. The improvement in CP and AA digestibility with autoclaving varied with the PPC used and was consistent with the reduction in TIA observed (9.4 to 2.8 mg/g for PPC-1 vs. 9.1 to 5.3 mg/g for PPC-2). The standardized ID (SID) of most indispensable AA was similar for the FSBM and the PPC-2 and higher for both than for the PPC-1 (P < 0.05). For Lys, the lowest SID value was observed for the FSBM and the highest for the PPC-2 either unheated or autoclaved. It is concluded that the ID of the AA of the PPC improved with heating and was in general higher for the autoclaved PPC than for the FSBM. Consequently, heat processed PPC is a good alternative to FSBM and unheated PPC in starter diets for broilers.

Effect of crude protein and fat content of diet on productive performance and egg quality traits of brown egg-laying hens with different initial body weight

A trial was conducted to study the influence of CP and fat content of the diet on performance and egg quality traits of brown egg-laying hens from 22 to 50 wk of age. The experiment was conducted as a completely randomized design with 8 treatments arranged factorially with 4 diets and 2 initial BW of the hens (1,592 vs. 1,860 g). Three of these diets differed in the CP content (16.5, 17.5, and 18.5%) and included 1.8% added fat. The fourth diet also had 18.5% CP but was supplemented with 3.6% fat instead of 1.8% fat. Each treatment was replicated 4 times, and the experimental unit consisted of 21 hens allocated into groups of 7 in 3 adjacent cages. All diets were isocaloric (2,750 kcal of AME/kg) and met the recommendations of brown egg-laying hens for digestible Arg, Ile, Lys, Met, Thr, Trp, TSAA, and Val. Productive performance and egg quality were recorded by replicate every 28 d. For the entire experimental period, diet did not affect any of the productive performance traits studied, but the heavier hens had higher ADFI (120.6 vs. 113.9 g; P < 0.001), egg production (92.5 vs. 89.8%; P < 0.01), and egg weight (64.9 vs. 62.4 g; P < 0.001) than the lighter hens. Initial BW did not affect feed conversion per kilogram of eggs or hen mortality, but BW gain was higher (289 vs. 233 g; P < 0.01) and feed conversion ratio per dozen of eggs was better (1.52 vs. 1.57; P < 0.01) for the lighter than for the heavier hens. None of the egg quality variables studied was affected by dietary treatment or initial BW of the hens. It is concluded that brown egg-laying hens, irrespective of their initial BW, do not need more than 16.5% CP to maximize egg production, provided that the diet meets the requirements for key indispensable amino acids. Heavier hens produce more eggs that are larger than lighter hens but feed efficiency per kilogram of eggs is not affected.

Hydrolyzed porcine mucosa in broiler diets: Effects on growth performance, nutrient retention, and histomorphology of the small intestine

The effect of including hydrolyzed porcine mucosa sprayed into soybean meal (HPM) in the diet was studied in broilers. In experiment 1 (pen study), 1,080 one-day-old chicks were used in a completely randomized design with 8 treatments arranged as a 4 × 2 factorial with 4 levels of HPM (0, 2.5, 5.0, and 7.5%) and 2 levels of Lys (1.23 and 1.38%). From d 1 to 22, HPM inclusion quadratically improved BW gain (BWG, P < 0.01) and feed conversion ratio (FCR, P < 0.01). From d 1 to 8, birds fed 1.38% Lys had higher BWG (P < 0.05) and better FCR (P < 0.05) than birds fed 1.23% Lys but only a trend (P < 0.08) for improved BWG was detected from d 1 to 22. From d 22 to 37, a period in which all birds received a common finisher diet, growth performance was not affected by the previous starter diet. In experiment 2 (battery study), birds were fed for 37 d the same diets used in the starter period of experiment 1. Broilers fed HPM had higher BWG (linear, P < 0.05; Quadratic, P < 0.05) than birds fed control diet, and birds fed 1.38% Lys had higher BWG (P < 0.01) than birds fed 1.23% Lys. From d 1 to 22, BWG (P < 0.05) and ADFI (P < 0.01) increased quadratically and FCR improved linearly (P < 0.05) with HPM inclusion. Also in this period, BWG was higher at the higher Lys level (P < 0.01). Diet did not affect intestinal histomorphology of broilers on d 8 or nutrient retention on d 22. We conclude that the inclusion of 2.5 to 5% HPM in the diet improved growth performance of broilers from d 1 to 22. An increase in Lys from 1.23 to 1.38% improved growth performance up to 15 d of age, but not thereafter. Diet did not affect villus histomorphology or nutrient retention of the small intestine.