Estimation of the maximum safe level of feed ingredients by spline or broken-line nonlinear regression models

Determination of safe levels and toxic levels for feed hazardous materials in broiler chickens: a review

Feed safety is needed to produce and provide safe animal feeds for consumers, animals, and the environment. Although feed safety regulations have been set for each country, there is a lack of clear feed safety regulations for each livestock. Feed safety regulations are mainly focused on heavy metals, mycotoxins, and pesticides. Each country has different safe levels of hazardous materials in diets. Safe levels of hazardous materials in diets are mostly set for mixed diets of general livestock. Although there is a difference in the metabolism of toxic materials among animals, the safe level of feed is not specific for individual animals. Therefore, standardized animal testing methods and toxicity studies for each animal are needed to determine the correct safe and toxic levels of hazardous materials in diets. If this goal is achieved, it will be possible to improve livestock productivity, health, and product safety by establishing appropriate feed safety regulations. It will also provide an opportunity to secure consumer confidence in feed and livestock products. Therefore, it is necessary to establish a scientific feed safety evaluation system suitable for each country's environment. The chance of outbreaks of new hazardous materials is increasing. Thus, to set up appropriate toxic levels or safe levels in feed, various toxicity methods have been used to determine toxic levels of hazardous materials for humans and animals. Appropriate toxic testing methods should be developed and used to accurately set up and identify toxicity and safe levels in food and feed.

Effects of palm kernel cake on nutrient utilization and performance of grazing and confined cattle: a meta-analysis

A meta-analysis was conducted to evaluate the effects of dietary palm kernel cake inclusion (PKC_Inclusion) on the nutrient intake and digestibility, as well as on the performance of cattle under grazing and confined systems. Additionally, potential maximum safe levels (MSL) for PKC_Inclusion were explored for cattle under those systems using a broken-line approach. Overall, 22 studies for 85 treatment means and 747 experimental units were included in the dataset used for the meta-analysis in which, quantitative responses to increasing PKC_Inclusion levels were fitted using a mixed model, considering the study as a random effect. Additionally, all studies tested a treatment without the inclusion of PKC (PKC_Inclusion = 0 g/kg DM) in the concentrate and total mixed ration fed to grazing and confined animals, respectively. In grazing animals, intake, and digestibility of dry matter (DM), as well as intake of total digestible nutrient (TDN) and digestibility of crude protein (CP) decreased linearly (P < 0.01) as PKC_Inclusion increased. Conversely, the intake and digestibility of neutral detergent fiber (NDF) increased linearly (P < 0.01). Additionally, the intake of CP showed a quadratic decreasing pattern (P < 0.01) with the increase in dietary PKC_Inclusion. In confined animals, intake of DM, CP, NDF, and TDN revealed quadratic patterns (P < 0.01) as PKC_Inclusion increased. The digestibility of DM, CP, NDF, as well as TDN concentration showed a linear decreasing pattern (P < 0.05) as PKC_Inclusion increased. For performance, data revealed that average daily gain (ADG) decreased linearly (P < 0.01) in grazing and confined animals with the increase in PKC_Inclusion. Feed efficiency (FE) decreased linearly (P < 0.01) in grazing animals, whereas it showed a linear increase (P < 0.05) in confined animals. Exploration of the quadratic relationships of intake of DM, CP, NDF, and TDN with PKC_Inclusion in confined animals revealed MSL values for PKC ranging from 85.56 ± 14.2 to 126.4 ± 14.7 g PKC/kg DM. In grazing animals, exploration of the quadratic relationship of intake of CP with PKC_Inclusion, revealed an MSL value of 96.23 ± 9.01 g PKC/kg DM. In conclusion, data revealed that the use of PKC in both confined and grazing systems reduces the nutrient utilization and performance of cattle in a dose-dependent manner without a maximum safe level that does not reduce animal performance.

Growth Performance, Serum Biochemical Indices, Duodenal Histomorphology, and Cecal Microbiota of Broiler Chickens Fed on Diets Supplemented with Cinnamon Bark Powder at Prestarter and Starter Phases

Ross 308 broiler chicks (n = 240) aged 1 day were assigned to five groups for eight replicates (six chicks for each) (3♂ and 3♀). Basal dietary groups were supplemented by 2000, 4000, and 6000 mg/kg cinnamon (CN) for 21 days. Basal diet alone was used as a negative control, and basal antibiotic diet (Colimox) was used as a positive control. At 10, 14, and 21 days of age, chicks that received 2000 mg CN and Colimox had a higher body weight, resulting in an increase in body weight gain. CN also resulted in the maximum improvement in the feed conversion ratio and feed efficiency over 1-21 days at the level of 2000 mg/kg. At days 10, the maximum relative breast weight was 2000 mg/kg of CN. Mean serum albumin concentrations, duodenal villus height, and goblet cell density increased (p < 0.05) by 2000 mg/kg of CN, and mean serum globulin and total protein concentrations and crypt depth increased (p < 0.05) by 6000 mg/kg of CN compared with control. Increased cecal Escherichia coli number was CN dose-dependent. In conclusion, dietary inclusion of 2000 mg/kg CN can be applied as an alternative to in-feed antibiotics for broiler starter diet.

The effects of clove seed (Syzygium aromaticum) dietary administration on carcass characteristics, meat quality, and sensory attributes of broiler chickens

Previous studies have shown positive outcomes associated with the incorporation of cloves into broiler chicken diets. This study aimed to evaluate carcass characteristics, meat quality, and sensory attributes of broiler chickens fed diets supplemented with different clove seed levels. A total of 240 day-old Ross 308 broiler chicks were fed 1 of seven dietary treatments. The control group diet contained 0% clove seeds, whereas the treatment group diets contained up to 6% clove seeds. The chickens' final BW was significantly different between the treatments, which decreased linearly with increasing levels of clove seed inclusion. Broiler chickens fortified with clove seeds did not significantly affect the chickens' carcass characteristics and body composition. However, an increment in weights of carcass components (liver, heart, and gizzard) was observed in low clove seed levels. In addition, water-holding capacity, cooking loss percentages, and tenderness of the meat were improved owing to clove seed inclusion (1 or 2%) compared with the control group. Further studies are warranted to optimize the outstanding use of cloves toward broiler chicken performance enhancement and to produce a high quality of meat.

Comparison of toxic effects of dietary organic or inorganic selenium and prediction of selenium intake and tissue selenium concentrations in broiler chickens using feather selenium concentrations

The present experiment aimed to compare toxic effects of dietary organic or inorganic selenium (Se) and to predict of Se intake and tissue Se concentrations in broiler chickens based on feather Se concentrations. A total of four hundred twenty 7-day-old Ross 308 male broiler chicks were allotted to 1 of 7 dietary treatments in a completely randomized design. Each treatment had 6 replicates with 10 birds per replicate. Organic Se (selenium yeast) or inorganic Se (sodium selenite) was added to the basal diet at the levels of 5, 10, or 15 mg/kg Se. All experimental diets were fed to birds on an ad libitum basis for 28 d. Results indicated that a significant interaction (P < 0.01) was observed between Se sources and inclusion levels for the BW gain and feed intake of broiler chickens with inorganic Se at 15 mg/kg in diets showing a greatest negative effect. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) plasma concentrations of uric acid. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) relative liver weight. No significant interactions were observed between Se sources and inclusion levels in diets on hepatic antioxidant capacity. Increasing inclusion levels of Se in diets increased (linear, P < 0.01) Se concentrations in the liver, breast, and feather. The concentrations of Se in the breast, liver, and feather were greater (P < 0.05) for organic Se than for inorganic Se in diets. The toxic levels of organic or inorganic Se in broiler diets were near 7 or 9 mg/kg based on the BW gain, respectively. The prediction equations indicate that feather Se concentrations in broiler chickens can be used to predict both daily Se intake and Se concentrations in the liver and breast.

Rumex nervosus leaves meal improves body weight gain, duodenal morphology, serum thyroid hormones, and cecal microflora of broiler chickens during the starter period

A total of 192 one-day-old Ross 308 broiler chicks were assigned to 4 treatments with 8 replicate cages of 6 chicks (3♀ and 3♂) per cage according to a completely randomized block design. The dietary treatments were a basal diet (control) and a control diet supplemented with 1,000, 3,000, and 5,000 mg/kg Rumex nervosus leaves meal (RN). Gallic acid and some volatile compounds were detected in the RN extract. On day 10 of age, BW was improved (P = 0.016) with supplemental RN (1,000-5,000 mg/kg). On day 14 of age, dietary application of RN up to 3,000 mg/kg increased BWG (P = 0.003) compared with control, while a 1,000 mg/kg RN had the best feed conversion ratio (P = 0.016). On day 10 of age, samples were taken on a single female bird per replicate. The addition of RN (1,000-5,000 mg/kg) increased (P < 0.001) serum albumin and triiodothyronine levels and maximized the relative weight of breast meat (P = 0.003). Feeding a diet with 1,000 mg/kg RN resulted in greater duodenal villus height (P < 0.001) than control and the diet with 5,000 mg/kg RN. Broilers fed diet supplemented with 1,000 mg/kg RN had the best duodenal villus surface area (P < 0.001). Feeding a diet with 1,000 mg/kg RN decreased (P < 0.001) cecal Escherichia coli count compared with control and the diet with 5,000 mg/kg RN. Salmonella spp. count tended to increase with 5,000 mg/kg RN leaves meal (P = 0.069, linear P = 0.026). In conclusion, R. nervosus leaves meal could be considered as a phytogenic feed additive in broiler diets up to a 1,000-mg/kg inclusion rate because of its combined positive effects on BWG, feed conversion ratio, villus height, villus surface area, serum albumin and triiodothyronine hormone, and cecal E. coli during the starter period (day 10-14 of age). Further study is required to elucidate its molecular mechanism.

Effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens

The objectives of the current experiment were to investigate the effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens. Finally, the safe levels of melamine in broiler diets were determined based on BW gain (BWG) and melamine residue in the breast meat. A total of 1,008 1-d-old Ross 308 male and female broiler chickens were allotted to 1 of 7 dietary treatments within each sex in a completely randomized design. There were 6 replicates per treatment and each replicate consisted of 12 birds. Dietary melamine concentrations were set to 0; 250; 500; 750; 1,000; 5,000; or 10,000 mg/kg by adding a purified form of melamine. Diets were provided to birds on ad libitum basis for 35 d. Results indicated that no significant interaction between sex and dietary melamine concentrations was observed for all measurements. The BW, BWG, and feed intake for birds fed diets containing 10,000 mg/kg melamine were less (P < 0.05) than for those fed other diets. Melamine residues in the kidney and breast for birds fed diets containing 10,000 mg/kg melamine were greater (P < 0.05) than for birds fed other diets. The toxic level of dietary melamine based on BWG was determined by the one-slope broken-line analysis. The resulting equation was Y = 1,851 - 0.0404 × (X - 4,292), which indicated that a greater than 4,292 mg/kg melamine in diets was toxic to broiler chickens. The safe level of dietary melamine to limit melamine residue in the broiler breast was analyzed using the linear regression, which indicated that the safe level of melamine in broiler diets was 814 mg/kg. In conclusion, less than 814 mg/kg melamine in broiler diets should be maintained to satisfy human food safety regulations for melamine residue in the breast meat of broiler chickens.

Nutritive value and the maximum inclusion level of pennycress meal for broiler chickens

Two experiments were conducted to evaluate the nutritive value and maximum safe level (MSL) of pennycress meal (PM) for broiler chicks. In experiment 1, a total of 480 chicks was fed either mash or crumbled diets containing zero, 5, 10, or 15% PM for 18 d (8 diets; 6 replications per diet). In experiment 2, a total of 660 chicks was fed mash diets containing zero, 3, 6, 9, 12, or 15% of either PM or canola meal (CM; a comparative reference) for 14 d (11 diets; 6 replications per diet). Analytical results show that PM is a good source of protein (∼31% CP) and it is very comparable to CM (∼36% CP). However, it contains higher erucic acid (∼1.68 vs. < 0.021%), glucosinolates (sinigrin) (∼63.5 vs. <0.163 μmol /g), and crude fiber (18.60 vs. 9.27%) compared to CM. In experiment 1, increasing PM from zero to 15% resulted in linear reductions (P < 0.05) in FI, BWG, and FCR at 10 days. Above 10%, performance responses were affected for FI and BWG at 18 d, respectively. An estimated MSL of 10% PM based on orthogonal contrast was optimal for satisfactory FI and BWG. The MSL as estimated by broken-line linear (BLL) and broken-line quadratic (BLQ) models was 9.12 ± 0.50 and 7.0 ± 1.27%, respectively. In experiment 2, growth performance at 14 d was reduced above 9% due to PM inclusion. CM inclusion did not affect growth performance at 14 d, suggesting 15% to be safe. The MSL for maximum growth performance varied depending on the statistical analysis as follows: 12% by orthogonal contrast and LSD, 15% by the Scheffé test, 10.84 ± 0.57 by BLL, and 8.61 ± 1.29 by BLQ. In conclusion, PM can be included in broiler starter diets as a protein source but its inclusion should be limited to no more than 8.5%. Different statistical procedures give different MSL and this should be considered when interpreting the data.

Evaluation of different agroindustrial waste on the effect of different carcass characteristics and physiological and biochemical parameters in broilers chicken

Aim:

This study was conducted to evaluate the physiological and biochemical effect in chickens of the Ross breed of a food enriched with agroindustrial waste.

Materials and Methods:

The food is one of the main components of the total cost for the production of chickens. Rations should be formulated to provide the correct balance of energy, protein, amino acids, minerals, vitamins and essential fatty acids, to allow optimal growth and performance. This study was intended to evaluate a natural feed for chicken, made from corn, yucca meal, eggshells, orange peel, soybean meal, salt and garlic, enriched with agroindustrial waste (molasses, milk whey and ferment of coffee). The weight gain was evaluated in broilers using a diet enriched with different agroindustrial wastes, with respect to a control food of the same composition but not containing residue. To develop the experiment 120 male Ross 308 chicks were used, these were evaluated for 6 weeks. Physicochemical test for the food and the agroindustrial waste were performed; moisture was determined; organic carbon, organic material and the ash, to characterize the agroindustrial wastes, the reducing sugars content using a spectrophotometer at 540 nm and proteins through the Kjeldahl method was evaluated. During the experiment, the weight gain of chickens and feed conversion was evaluated; the end of the experiment the weight of eviscerated channel relative weight breast, thighs, pancreas, and abdominal fat was determined, besides including blood chemistries as determination of cholesterol, triglycerides, and glucose. Finally, the microbiological analyzes to detect the presence of Escherichia coli in the cecum was determinate. Data were analyzed by InfoStat statistical program using the generalized linear model procedure. The statistical comparison was made by Tukey test at the 95% probability level.

Results:

After the evaluation, fed chickens with the treatments food + milk whey (FMW) and food + ferment of coffee (FFC) demonstrated increased from 1949 to 1892 g, respectively, to the 42 days of evaluation, showing the best treatment for weight gain. However, the FFC treatment showed the best feed conversion reaching values of 1.79 related to levels of blood glucose (249 mg/dl). Even so the eviscerated channel yields were higher for the treatment FFC reaching 1810.1 g unlike the treatment FMW which it reached a weight of 1718.2 g with increased formation of abdominal fat (7.4 g) unlike other treatments. From the results, it is concluded that food enriched with coffee ferment allows an increase in weight, better feed conversion in addition to high production of lean meat.

Conclusion:

It was shown that the best treatment was the food enriched with the ferment of coffee, due to increased intake and weight gain at the end of 42 days of the experiment.