Effects of Dietary L-Carnitine Supplementation and Protein Level on Performance and Degree of Meatness and Fatness of Broilers

Effects of Dietary Supplementation of L-Carnitine and Mannan-Oligosaccharides on Growth Performance, Selected Carcass Traits, Content of Basic and Mineral Components in Liver and Muscle Tissues, and Bone Quality in Turkeys

The study aimed to determine the effect of L-carnitine and Bio-Mos administration on selected production performance, slaughter parameters, elemental and mineral content of liver, breast and thigh muscles, and physical, morphometric, strength and bone mineral composition parameters of turkeys. The experiment was conducted on 360 six-week-old Big-6 turkey females, randomly divided into three groups of 120 birds each (six replicates of 20 birds). The turkeys of the control group were fed standard feed without additives; group II was fed with drinking water, a preparation containing L-carnitine at a dose of 0.83 mL/L, while group III was provided mixed feed with 0.5% Bio-Mos. The addition of L-carnitine and Bio-Mos increased body weight at 16 weeks (p = 0.047) and reduced the proportion of fat in the breast muscle (p = 0.029) and liver (p = 0.027). It also modified the content of some minerals in breast muscle, thigh muscle, liver, and bone. Furthermore, the addition of L-carnitine and Bio-Mos increased bone mass and length and modified the value of selected morphometric and strength parameters. The results indicate a positive effect of the applied feed additives on selected rearing indices and carcass quality while improving the elasticity and fracture toughness of the femur. There is a need for further research to determine optimal doses of L-carnitine and Bio-Mos in poultry nutrition.

Basic mechanisms of the regulation of L-carnitine status in monogastrics and efficacy of L-carnitine as a feed additive in pigs and poultry

A great number of studies have investigated the potential of L-carnitine as feed additive to improve performance of different monogastric and ruminant livestock species, with, however, discrepant outcomes. In order to understand the reasons for these discrepant outcomes, it is important to consider the determinants of L-carnitine status and how L-carnitine status is regulated in the animal's body. While it is a long-known fact that L-carnitine is endogenously biosynthesized in certain tissues, it was only recently recognized that critical determinants of L-carnitine status, such as intestinal L-carnitine absorption, tissue L-carnitine uptake, endogenous L-carnitine synthesis and renal L-carnitine reabsorption, are regulated by specific nutrient sensing nuclear receptors. This review aims to give a more in-depth understanding of the basic mechanisms of the regulation of L-carnitine status in monogastrics taking into account the most recent evidence on nutrient sensing nuclear receptors and evaluates the efficacy of L-carnitine as feed additive in monogastric livestock by providing an up-to-date overview about studies with L-carnitine supplementation in pigs and poultry.

The effect of vitamin E, L-carnitine, and ginger on production traits, immune response, and antioxidant status in two broiler strains exposed to chronic heat stress

The present study was designed to find the effect of natural and synthetic antioxidants on the performance of two broiler strains under high ambient temperature. A total of 320 day-old chicks of Hubbard and Cobb were reared for a period for 21 days under the same nutritional and management systems. On day 21 onward, one subgroup was kept as control while other subgroups were provided with vitamin E (250 mg/kg), ginger (2 g/kg), and L-carnitine (500 mg/kg) in basal diets. Body weight and feed conversion ratio (FCR) were significantly (P < 0.05) high in vitamin E-supplemented birds, while feed intake was significantly (P < 0.05) higher in L-carnitine supplemented birds irrespective of the strain. Antibody titer against infectious bursal disease (IBD) and paraoxonase (PON1) was significantly (P < 0.05) higher in vitamin E-supplemented birds compared to the other treatments. The number of heterophils and toal oxidant status (TOS) were significantly (P < 0.05) lower in vitamin E-supplemented birds. Blood glucose was significantly (P < 0.05) lower in vitamin E-supplemented birds, while total protein was significantly (P < 0.05) higher in vitamin E-supplemented group. In conclusion, the supplementation of vitamin E at the rate of 250 mg/kg improved the antioxidant status and immune response in the two broiler strains. Further, the two strains perform similarly in terms of performance and other health status parameters with no significant difference.

Effects of dietary soybean and sunflower oils with and without L-carnitine supplementation on growth performance and blood biochemical parameters of broiler chicks

Abstract. An experiment was designed to investigate the effects of soybean, sunflower oil and dietary L-carnitine supplementation on growth performance, some blood biochemical parameters and antibody titer against Newcastle disease of broiler chicks. A 5-week feeding trial, 240 1-day old male broiler chicks (Ross 308) were randomly allocated to six dietary treatments as a 3 × 2 factorial experimental design where three sources of dietary oil contained soybean, sunflower and soybean plus sunflower oil with and without 120 mg kg−1 of L-carnitine supplementation in the diet. Results showed that soybean oil with L-carnitine significantly improved body weight gain and feed conversion ratio of broiler chicks in the grower and total period of rearing (p < 0.05). L-carnitine supplementation significantly increased total protein, globulin, cholesterol, HDL and LDL (high- and low-density lipoprotein) of blood serum in broiler chicks (p < 0.05). L-carnitine supplementation increased antibody titer against Newcastle disease of chicks and the highest levels were observed in those with the supplement of L-carnitine in the soybean oil dietary treatment. Results of this experiment showed that the growth performance and blood biochemical responses of broiler chicks to dietary supplementation with L-carnitine in dietary oil source and soybean oil, in comparison to sunflower oil, is the better plant oil for growth and immunological performance of broiler chicks.

Effects of breeder hen age and dietaryL-carnitine on progeny embryogenesis

1. Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg (8 replications per treatment) from 21 weeks of age. 2. Hens were inseminated with semen from Ross broiler breeder males. In a common facility, subsequent progeny hatchability and embryonic mortality at 25, 30, 32, and 38 weeks of breeder age were evaluated. 3. Subsequent egg component weights, incubational egg water loss, progeny embryo growth, and embryo, yolk sac and liver composition through 18 d of incubation at 27, 32, and 38 weeks of breeder age were evaluated. 4. Calculated additions of L-carnitine were in agreement with analysed contents of 3.5 and 31.1 mg free L-carnitine/kg of diet, respectively, and total L-carnitine concentrations increased by 48.6, 21.7, and 10.0% in 0-d yolk, 18-d yolk sac, and 18-d liver samples, respectively, due to the addition of dietary L-carnitine. 5. Supplemental L-carnitine resulted in increased (0.6%) relative 0-d egg yolk weight across weeks 27, 32, and 38, and reduced (0.38%) 18-d yolk sac palmitoleic acid concentration at week 27 without altering embryogenesis. 6. In conclusion, dietary L-carnitine (25 mg/kg of the diet) was deposited in the yolks of broiler breeder hens and was subsequently transferred to the embryonic liver via yolk sac absorption through 18 d of incubation. Furthermore, dietary L-carnitine supplementation increased ovarian follicle yolk deposition in 27-, 32-, and 38-week-old breeder hens, and influenced yolk sac fatty acid beta-oxidation in embryos from 27-week-old breeder hens causing yolk sac palmitoleic acid concentrations to be reduced by 18 d of incubation.

Effects of L-carnitine supplementation of diets differing in energy levels on performance, abdominal fat content, and yield and composition of edible meat of broilers

Responses to supplemental dietaryl-carnitine of broilers fed on diets with different levels of metabolizable energy (ME) were investigated using growth performance and some carcass measurements. Three isonitrogenous diets containing 13.5, 12.8 or 12.2 MJ ME/kg were formulated, with or without supplementall-carnitine (50mg/kg) and fedad libitumfrom 18 to 53 d of age. Supplementall-carnitine increased body-weight gain (BWG) and improved feed conversion (FC) during the first 2 weeks of study. FC was also improved during the fourth week of the experiment. Weights of breast yield and thigh meat yield were significantly increased, whereas quantity and percentage of abdominal fat were reduced by supplementall-carnitine. A significant interaction between supplemental dietaryl-carnitine and dietary energy level was noted for BWG and FC during the second week of study.

Dietary L-carnitine supplementation increases antigen-specific immunoglobulin G production in broiler chickens

The usefulness of supplementary dietary L-CARNITINE AS AN IMMUNOMODULATOR TO INCREASE ANTIGEN-SPECIFIC ANTIBODY LEVELS WAS ANALYSED IN 2–6-WEEK-OLD BROILERS. THE CHICKENS RECEIVED COMMERCIAL FEEDS EITHER UNSUPPLEMENTED (STARTER FEED 17·8 MG CARNITINE/KG, FINISHER DIET 22·9 MG CARNITINE/KG) OR SUPPLEMENTED WITH l-carnitine (100 mg carnitine/kg added to feed). At 14 d of age, both groups were distributed in equal numbers and sex ratios over two environmentally controlled chambers where temperature (28°) was either reduced immediately to 20°, or gradually to 22° at 36 d of age. Antigen-specific immunoglobulin (Ig)M, IgG, IgA and total Ig responses were measured following two immunizations with bovine serum albumin (BSA). The typical BSA-specific IgM responses followed by IgG responses to the primary immunization were boosted by the secondary immunization. The kinetics of these responses were not altered by l-carnitine treatment. However, BSA-specific total Ig and IgG, but not IgM, responses were significantly increased by dietary l-carnitine supplementation, after both the primary and the secondary immunization. No significant influence of the sex of the chicks or the imposed environmental temperature on Ig responses was found. Temperature treatment and sex, but not l-carnitine supplementation, did significantly influence body-weight gain: cockerels were heavier than females and this became most evident in the second half of the rearing period. Further, lowering the temperature increased body weight. In conclusion, dietary l-carnitine supplementation appeared to be beneficial in enhancing specific humoral responses on vaccination.

Effects of dietary L-carnitine and coenzyme Q10at different supplemental ages on growth performance and some immune response in ascites-susceptible broilers

Effects of dietary L-carnitine and coenzyme Q10 (CoQ10) at different supplemental ages on performance and some immune response were investigated in ascites-susceptible broilers. A 3 x 2 x 2 factorial design was used consisting of L-carnitine supplementation (0, 75, and 100 mg/kg), CoQ10 supplementation (0 and 40 mg/kg) and different supplemental ages (from day 1 on and from day 10 on). A total of 480 one-day-old Arbor Acre male broiler chicks were randomly allocated to 12 groups, every group had five replicates, each with eight birds. The birds were fed a corn-soybean based diet for six weeks. From day 10-21, all the birds were exposed to a low ambient temperature (12-15 degrees C) to increase the susceptibility to ascites. No significant effects were observed on growth performance by L-carnitine, CoQ10 supplementation, and different supplemental ages. Packed cell volume was significantly decreased by L-carnitine supplementation alone, and ascites heart index and ascites mortality were decreased by L-carnitine, CoQ10 supplementation alone, and L-carnitine + CoQ10 supplementation together (p < 0.05). Heart index of broilers was significantly improved by L-carnitine, CoQ10 supplementation alone during 0-3 week. Serum IgG content was improved by L-carnitine supplementation alone (p < 0.05), but lysozyme activity was increased by L-carnitine + CoQ10 supplementation together (p < 0.05). A significant L-carnitine by supplemental age interaction was observed in lysozyme activity. L-carnitine supplementation alone had no effects on the peripheral blood lymphocyte (PBL) proliferation in response to concanavalin A (ConA) and lipopolysaccharide, but supplemental CoQ10 alone and L-carnitine+ CoQ10 together decreased the PBL proliferation in response to ConA (p < 0.05). The present study suggested that L-carnitine + CoQ10 supplementation together had positive effects on some immune response of ascites-susceptible broilers, which might benefit for the reduction of broilers' susceptibility to ascites.

Breeder hen dietary L-carnitine affects progeny carcase traits

(1) Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg from 21 weeks of age. (2) Hens were inseminated with semen from Ross broiler breeder males and subsequent growth performance and carcase traits, of progeny obtained from hatches at 30, 35 and 37 weeks of age, were evaluated. (3) Progeny were hatched in a common facility and separated by gender. Experimental treatments employed for the 30-, 35- and 37-week hatches, respectively, were: hen diet and progeny gender (16 replications with two subplots); hen diet, progeny diet (0 and 50 mg L-carnitine/kg of diet) and progeny gender (16 replications with 4 subplots); and hen diet and progeny diet (high and low density; 16 replications with two subplots). (4) Females had lower growth rate and less breast meat, but greater proportions of carcase fat and breast meat than males. Growth performance measurements of progeny were not affected by hen L-carnitine, but hen L-carnitine decreased abdominal fat in progeny. Increasing diet density in the chick diets increased growth and carcase weights. Hen and progeny dietary L-carnitine interacted to increase male mortality. However, dietary hen L-carnitine decreased carcase fat and increased breast meat in progeny fed on high nutrient density diets. (5) In conclusion, L-carnitine in the diet of hens affected carcase traits of their progeny.

Effects of L-carnitine on growth performance, carcass composition, and metabolism of lipids in male broilers

We studied the effects of L-carnitine on growth performance, carcass composition, and lipid metabolism in male broilers. Six hundred male commercial broilers were allotted to five groups, each of which included three replicates (40 birds per replicate). The groups received the same basal diet supplemented with 0, 25, 50, 75, or 100 mg/kg L-carnitine, respectively. The feeding trial showed that L-carnitine had no significant effect on daily gain or feed conversion. Supplementation with L-carnitine (above 25 mg/kg) in the diet increased breast muscle yield (P < 0.05) and crude fat content of the muscles and decreased abdominal fat content (P < 0.05). Addition of 50, 75, or 100 mg/kg L-carnitine to the diet decreased total activities of glucose-6-phosphate dehydrogenase, malic dehydrogenase, isocitrate dehydrogenase, and lipoprotein lipase (P < 0.05) in the subcutaneous fat and total activity of carnitine palmitoyltransferase-I (P < 0.05) in breast muscles. The results of this study indicate that L-carnitine could reduce the deposit of subcutaneous fat by decreasing total activities of enzymes in the fat and enhance intramuscular fat by decreasing the activity of carnitine palmitoyltransferase-I in breast muscles.

Effects of dietary supplemental L-carnitine and ascorbic acid on performance, carcass composition and plasma L-carnitine concentration of broiler chicks reared under different temperature

The present study was initiated to determine whether dietary supplemental L-carnitine and ascorbic acid affect growth performance, carcass yield and composition, abdominal fat and plasma L-carnitine concentration of broiler chicks reared under normal and high temperature. During the experiment, two temperature regimes were employed in two experimental rooms, which were identical but different in environmental temperature. The regimes were thermoneutral (20-22 degrees C for 24 h) or recycling hot (34-36 degrees C for 8 h and 20-22 degrees C for 16 h). One-day-old broiler chicks (ROSS) were used in the experiment. A 2 x 2 x 2 factorial arrangement was employed with two levels (0 and 50 mg/kg) of supplemental L-carnitine and two levels (0 or 500 mg/kg) of supplemental ascorbic acid in drinking water under thermoneutral or high temperature regimes. Body weight gain was affected by high temperature. However, body weight gain was significantly improved in animals receiving supplemental L-carnitine, ascorbic acid or L-carnitine + ascorbic acid compared to animals receiving unsupplemented diet under high temperature. On the other hand, supplemental L-carnitine or L-carnitine + ascorbic acid reduced body weight gain under thermoneutral condition. Supplemental ascorbic acid significantly improved feed conversion efficiency, the improvement was relatively greater under high temperature. The L-carnitine content in the plasma was higher in the groups receiving supplemental L-carnitine and ascorbic acid under high temperature, while broilers fed supplemental L-carnitine and ascorbic acid had a decreased level of plasma L-carnitine concentration under normal temperature. It is concluded that dietary supplemental L-carnitine or L-carnitine + ascorbic acid may have positive effects on body weight gain, carcass weight under high temperature conditions.

Dietary L-carnitine increases plasma insulin-like growth factor-I concentration in chicks fed a diet with adequate dietary protein level

1. The effect of L-carnitine supplemented into experimental diets with varying dietary protein concentrations (50, 200 and 400 g/kg) on body weight gain and plasma insulin-like growth factor-I (IGF-I) concentration in chicks was examined. 2. Dietary L-carnitine supplementation provided 0, 200, 500 and 1000 mg/kg. Chicks were given the diet ad libitum for 10 d. 3. When L-carnitine was provided as 500 or 1000 mg/kg, body weight gain was significantly improved in birds receiving the 200 and 400 g protein/kg diets. 4. There was an interaction between dietary L-carnitine and protein content on plasma IGF-I concentration. L-carnitine supplementation had little influence on plasma IGF-I concentrations in birds receiving the low protein (50 g/kg) diet. When dietary L-carnitine concentrations were increased from 0 to 1000 mg/kg in the adequate protein (200 g/kg) diet, plasma IGF-I concentrations were also increased. However, when dietary L-carnitine content was more than 500 mg/kg in the 400 g/kg protein group, plasma IGF-I concentration decreased with increasing dietary L-carnitine content. 5. Body weight change correlated significantly with the alteration in plasma IGF-I concentrations in chicks given diets with adequate dietary protein. 6. In conclusion, the improvement in body weight gain caused by dietary L-carnitine supplementation was achieved when chicks were given their dietary protein requirement, which may be partially explained by an increase in plasma IGF-I concentration.

The effects of dietary L-carnitine supplementation on the performance, organ weights and circulating hormone and metabolite concentrations of broiler chickens reared under a normal or low temperature schedule

1. The present study examined the effects of the addition of 100 mg/kg L-carnitine to the basal starter (containing 17.8 mg/kg L-carnitine) and finisher (containing 22.9 mg/kg L-carnitine) diets on performance, organ weights and plasma hormone and metabolite concentrations of male and female broiler chickens. The broiler chickens were reared either in a room with a normal temperature (NT) program or with a low temperature (LT) program (rapid decrease from 28 degrees C to 20 degrees C at 14 d of age). 2. Broiler chickens reared under the LT schedule consumed more food and attained a greater body weight at 42 d of age than their counterparts reared under NT schedule, without any difference in food efficiency or abdominal fat content. Dietary L-carnitine supplementation had no significant effects on any of these production parameters, except for a reduction in the abdominal fat content of female NT chickens. However, the LT schedule and dietary L-carnitine supplementation greatly increased absolute and proportional heart weights. The elevated heart weights were not due to right ventricle hypertrophy. 3. Both the LT program and L-carnitine supplementation increased circulating plasma triiodothyronine concentrations. There were also some transient effects of both experimental variables on plasma growth hormone, glucose and triglyceride concentrations. 4. L-carnitine did not improve broiler performance. However, this result does not mean that L-carnitine supplementation cannot have beneficial effects in other circumstances. In view of the elevated proportional heart weights, it can also be argued that L-carnitine is a potential agent for reducing the incidence of metabolic diseases in broiler chickens.