You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


1. Introduction {#sec1}
===============

Benzoic acid was superior to other acids in terms of *in vitro* bactericidal effects on coliforms ([@bib6]) and enhanced growth performance of piglets by the strong antimicrobial effects in the gastrointestinal tract ([@bib5]).

In piglets, there is a plethora of studies with benzoic acid. Benzoic acid (0.5%) improved growth rate, feed intake, and feed utilization rate in piglets ([@bib5], [@bib15], [@bib4]). This could be attributed to the improved gut health via decreasing digesta pH value, increasing the number of *Bifidobacterium* while decreasing *Escherichia coli*, promoting the development of intestinal morphology ([@bib1]), enhancing jejunal antioxidant capacity ([@bib2]), diversifying ileal microbiota ([@bib15], [@bib4]), and increasing utilization rates of nutrients ([@bib3]). There is, however, a lack of long-term studies to ascertain the positive effects of benzoic acid on pigs from weaning until slaughter ([@bib4]). Moreover, the finding by [@bib14] that adding between 2.5% and 5.0% benzoic acid could lead to organ injury in piglets makes it imperative to study benzoic acid during the entire grower-finisher period at the recommended levels which are usually less than 1%.

In the current study, 2 experiments were conducted to validate the efficacy of benzoic acid on the growth performance of both nursery and grower-finisher pigs.

2. Materials and methods {#sec2}
========================

The animal protocol for this research was approved by the Animal Welfare Committee of DSM (China) Animal Nutrition Research Center (AWCCAN).

2.1. Animals and facilities {#sec2.1}
---------------------------

### 2.1.1. Experiment one {#sec2.1.1}

A total of 144 PIC L1050 barrows (initial body weight 7.1 ± 0.6 kg and final body weight 20.0 ± 2.7 kg) were used. Six barrows were housed in a pen (3.0 m × 1.8 m) furnished with 2 nipple drinkers and one trough with a stocking density at 0.9 m^2^ per pig. The study lasted for 28 days in two 14-day phases.

### 2.1.2. Experiment two {#sec2.1.2}

A total of 288 PIC L1050 barrows (initial body weight 36.1 ± 3.6 kg and final body weight 112.4 ± 8.4 kg) previously not exposed to benzoic acid were used. Six barrows were housed in a pen (4.9 m × 2.7 m) furnished with 2 nipple drinkers and one trough with a stocking density at around 2.2 m^2^ per pig. The experiment lasted 70 days in two 35-day phases.

### 2.1.3. Facilities {#sec2.1.3}

The experiments were conducted at DSM (China) Animal Nutrition Research Center Co., Ltd. (Bazhou, China). Room temperature was controlled by a computer system to maintain an optimal environment according to the age of pigs. Water and feed in pellet form were supplied *ad libitum*. The lighting was set as bright during the day and as dim during the night.

2.2. Experimental design {#sec2.2}
------------------------

Both experiments were in a randomized complete block design with the initial body weight of pigs as the blocking factor. There was a total of 3 dietary treatments with each treatment in 8 replicate pens in experiment 1 and 16 replicate pens in experiment 2. The 3 treatments corresponded to 3 dietary levels of benzoic acid: 0, 0.3%, and 0.5%. The ingredient and nutrition compositions of the basal diets are shown in [Table 1](#tbl1){ref-type="table"}. The analyzed nutrients and benzoic acid are shown in [Table 2](#tbl2){ref-type="table"}.Table 1Ingredients and nutrient compositions of basal diets (as-fed basis).Table 1ItemNurseryGrowerFinisherIngredients, g/kgCorn (7.8%)611.00760.00831.00Soybean meal (47%)245.00----Soybean meal (43%)--200.00130.00Fishmeal (65%)50.00----Whey powder (3%)50.00----Soybean oil15.008.008.00NaCl3.003.503.50Limestone7.008.958.50Dicalcium phosphate2.754.003.05[l]{.smallcaps}-lysine·HCl4.003.704.00[dl]{.smallcaps}-methionine0.800.500.30[l]{.smallcaps}-threonine1.301.001.20[l]{.smallcaps}-tryptophan--0.200.30Phytase0.150.150.15Treatment premix[1](#tbl1fn1){ref-type="table-fn"}5.005.005.00Vitamins and minerals premix 4205[2](#tbl1fn2){ref-type="table-fn"} (0.5%)5.00----Vitamins and minerals premix 4305[3](#tbl1fn3){ref-type="table-fn"} (0.5%)--5.00--Vitamins and minerals premix 4405[4](#tbl1fn4){ref-type="table-fn"} (0.5%)----5.00Total1,000.001,000.001,000.00Calculated nutrients & energy, %Crude protein20.215.513.0ME, kcal/kg3,4013,3253,329Total Ca0.840.630.57Total P0.690.530.48True total tract digestible P0.460.320.29Standardized ileal digestible amino acidLys1.280.910.78Met0.390.270.22Thr0.760.560.49Trp0.200.160.14Val0.800.560.47[^1][^2][^3][^4]Table 2Analyzed nutrients of the experimental diets with different levels of benzoic acid (BA).Table 2ItemDry matter, %Crude protein, %Total Ca, %Total P, %BA, mg/kgExperiment 10 BA88.219.40.740.5500.3% BA88.619.40.750.552,9420.5% BA88.919.90.740.554,206Experiment 2: grower (1)[1](#tbl2fn1){ref-type="table-fn"}0 BA87.516.00.580.4000.3% BA87.715.50.580.422,7860.5% BA87.915.30.560.404,699Experiment 2: grower (2)[1](#tbl2fn1){ref-type="table-fn"}0 BA87.315.50.570.3900.3% BA87.215.30.570.382,5100.5% BA87.615.70.590.405,156Experiment 2: finisher (1)[2](#tbl2fn2){ref-type="table-fn"}0 BA88.113.20.540.3600.3% BA88.313.10.520.352,8600.5% BA88.613.00.530.354,502Experiment 2: finisher (2)[2](#tbl2fn2){ref-type="table-fn"}0 BA87.813.10.550.3600.3% BA87.713.20.510.343,0380.5% BA88.013.10.520.364,597[^5][^6]

The nursery, grower, and finisher pigs\' diets were formulated to meet or exceed the energy and nutrients requirements for 11 to 25 kg, 50 to 75 kg, and 75 to 100 kg pigs in [@bib10], respectively. The feed was pelleted at 80 °C.

Benzoic acid with a purity of 99.5% and phytase were provided by DSM (China) Ltd. (Shanghai, China). Phytase at the supplementation level of 0.15 g/kg feed was assumed to provide 1.27 kg total P and 1.06 kg total Ca per ton of feed. The mineral and vitamin premixes were provided by DSM Vitamins (Shandong) Ltd. (Liaocheng, China).

2.3. Sampling and analyses {#sec2.3}
--------------------------

The pigs were weighed on d 0, 14, and 28 in experiment 1, and on d 0, 35 and 70 in experiment 2. Feed allowance and leftover were recorded in each 14- or 35-d period. The number of pig-days per period and pen was recorded.

After extraction in 1% acetic acid and anhydrous ethanol (3/2, vol/vol), benzoic acid was measured with HPLC (Agilent 1200 series, Agilent Technologies, Santa Clara, CA, USA) using benzoic acid as an external standard, a ZORBAX SB-C18 column, 0.5% formic acid/acetonitrile as the mobile phase, and a detection wavelength at 230 nm. Dietary samples were dried at 105 °C in an oven for 4 h for dry matter determination. Nitrogen content was determined by the Dumas method (LECO FP-528, LECO Corporation, St Joseph, MI, USA). Gross energy was determined using an adiabatic bomb calorimeter (C 2000 basic, IKA, Germany). Calcium and phosphorus were determined by Inductively Coupled Plasma-Optical Emission Spectrometry (Optima TM 8000, PerkinElmer, Shelton, USA).

2.4. Statistical analysis {#sec2.4}
-------------------------

### 2.4.1. Calculations {#sec2.4.1}

Average daily gain (ADG) was calculated by adding the individual weight gains in each pen and then dividing by the number of pig-days of that pen. Feed intake was measured by pen, and average daily feed intake (ADFI) was calculated by dividing the feed intake of each pen by the number of pig-days of that pen. Feed conversion ratio (FCR) was calculated by dividing ADFI by ADG.

### 2.4.2. Statistical model {#sec2.4.2}

Data were analyzed with GLM procedure of SAS 9.3 (SAS Institute, Inc., Cary, NC, USA) using the following statistical model with pen-aggregated data:$$Y_{\mathit{ijk}} = \mu + \alpha_{i} + \beta_{j} + \varepsilon_{\mathit{ijk}}\text{,}$$where *μ* is the overall mean, *α*~*i*~ is the effect of the ith block, *β*~*j*~ is the effect of the *j*th benzoic acid level, and *ε*~*ijk*~ is the error term.

Homogeneity of variance between treatment groups was checked by applying Levene\'s test. Normality was checked by applying Kolmogorov--Smirnov\'s method. To investigate the dose--response effect, orthogonal polynomial contrasts were used to test the linear and quadratic effects of benzoic acid. The contrast coefficients were generated using IML procedure of SAS considering the unequal spacing between the treatments. The statistical significance was defined at *P* \< 0.05. The least square means are presented.

3. Results {#sec3}
==========

3.1. Dietary analyses {#sec3.1}
---------------------

The analytical results ([Table 2](#tbl2){ref-type="table"}) were in an acceptable range to the respective target levels ([Table 1](#tbl1){ref-type="table"}) and indicated that there were no errors in experimental diets that were prepared.

3.2. Model assumptions {#sec3.2}
----------------------

Variance homogeneity was present in the data. For the normality test, only ADFI for the period of d 35 to 70 at the benzoic acid level of 0.3% in experiment 2 failed. Since the main measurements were all normally distributed, no transformation of the outcome was performed.

3.3. Growth performance {#sec3.3}
-----------------------

Three piglets in experiment 1 and 5 pigs in experiment 2 were culled out. The culled piglets were diagnosed of meningitis or enteritis, while the grower pigs were eliminated due to rectal prolapse, limping or enteritis.

In experiment 1, ADG of all growth phases increased linearly (*P* \< 0.05) with increasing supplementation of benzoic acid, which led to a linear improvement in average body weight on d 28 (*P* \< 0.05; [Table 3](#tbl3){ref-type="table"}). There was also an improvement in FCR of d 0 to 14 (linear effect: *P* \< 0.05) and in ADFI during d 14 to 28 and d 0 to 28 (linear effect: *P* \< 0.01) ([Table 3](#tbl3){ref-type="table"}).Table 3Growth performance of nursery pigs (Experiment 1).Table 3ItemBenzoic acid, %SEM*P*-value00.30.5L[1](#tbl3fn1){ref-type="table-fn"}Q[2](#tbl3fn2){ref-type="table-fn"}Number of replicates888Body weight, kgd 07.17.17.00.090.5150.306d 1412.012.312.60.250.0830.845d 2819.020.320.80.450.0130.723d 0 to 14ADG, g349369403150.0240.503ADFI, g476481509140.1290.420FCR1.361.311.270.030.0240.831d 15 to 28ADG, g507571583170.0040.387ADFI, g74280884618\<0.0010.875FCR1.471.421.450.020.5550.138d 0 to 28ADG, g428470493150.0060.872ADFI, g609645678150.0050.774FCR1.421.381.380.020.1180.439[^7][^8][^9]

In experiment 2, ADG during d 0 to 35 and d 35 to 70, and average body weight on d 35 were improved linearly (*P* \< 0.05) with increasing supplementation of benzoic acid ([Table 4](#tbl4){ref-type="table"}). Average daily gain of d 0 to 70 and average body weight on d 70 increased significantly in a both linear and quadratic manner. There was a linear improvement in FCR of all growth phases (*P* \< 0.05). The optimal dietary inclusion rate of benzoic acid was calculated at 0.36% by regressing ADG of d 0 to 70 against the supplemental levels of benzoic acid (*y* = −483.33*x*^2^ + 351.67*x* + 1,048, *r*^2^ = 1) ([Table 4](#tbl4){ref-type="table"}).Table 4Growth performance of grower-finisher pigs (Experiment 2).Table 4ItemBenzoic acid, %SEM*P*-value00.30.5L[1](#tbl4fn1){ref-type="table-fn"}Q[2](#tbl4fn2){ref-type="table-fn"}Number of replicates161616Body weight, kgd 036.136.036.30.100.3150.232d 3574.576.576.10.510.0220.112d 70109.8113.9113.50.76\<0.0010.048d 0 to 35ADG, g1,0891,1501,138160.0200.106ADFI, g2,4902,5442,524340.4150.425FCR2.292.212.220.020.0140.207d 36 to 70ADG, g1,0081,0691,069130.0010.123ADFI, g3,0853,1763,163340.0840.296FCR3.072.972.960.040.0250.435d 0 to 70ADG, g1,0481,1101,10311\<0.0010.051ADFI, g2,7872,8602,844300.1590.308FCR2.662.582.580.030.0070.230[^10][^11][^12]

4. Discussion {#sec4}
=============

Liver can efficiently extract 89% of the dietary benzoic acid to synthesize hippuric acid for clearance by kidneys with the urinary excretion of hippuric acid accounting for 85% of the benzoic acid intake, but the absorption of benzoic acid in the gut is a protracted process ([@bib7]), which means a longer time for benzoic acid to act in the gastro-intestinal tract. Benzoic acid could improve the microbiota ecosystem in the gut and enhance the metabolic functions of the gut. Dietary supplementation of benzoic acid decreased the pH value of digesta inileum, cecum, and colon of piglets ([@bib1]) and in crop, jejunum, and ceca of chickens ([@bib11]), which could be a critical factor for the selective suppression of the detrimental pathogens and the improved biodiversity of microbiota in the gut ([@bib6], [@bib15], [@bib4]). Longer villi and higher activities of trypsin, lipase, and amylase in the jejunum of piglets were reported in response to supplementation of benzoic acid ([@bib4], [@bib1], [@bib2]), which could support greater nutrient digestion and absorption by pigs as proved in the metabolism trials by [@bib3], [@bib13], and [@bib8]. The improved intestinal morphology could be related to the upregulation of mucosal glucagon-like peptide 2 (GLP-2) and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX; [@bib2]). In addition, the supplementation of benzoic acid reduced manure NH~3~ emission ([@bib4], [@bib8]), which could help improve the environmental conditions for pigs.

For piglets in the current trial, the linear relationship between the growth performance and the supplemental levels of benzoic acid suggest the possibility of further improvement in growth performance of piglets with dietary benzoic acid supplementation greater than 0.5%. [@bib5] showed that the dietary supplementation of 1% benzoic acid can further improve the growth performance of piglets when compared with the level of 0.5% benzoic acid. Previous trials ([@bib5], [@bib15], [@bib4]) showed that 0.5% benzoic acid can improve ADG by 11% to 16%, ADFI by 8% to 11%, and FCR by 2% to 6% compared to the non-supplemented control, which compared with improvements of 15%, 11%, and 3% accordingly in the current study. It is worth noting that approximately 70% of improvement in ADG could be explained by the increase in ADFI in experiment 1, which is in agreement with the positive correlation between the effects of organic acid on ADG and ADFI ([@bib12]).

In the literature, there is evidence that benzoic acid might be able to improve the growth performance of grower-finisher pigs. For example, benzoic acid (2%) increased apparent P and Ca digestibility, and reduced urinary pH and NH~3~ emissions in grower pigs ([@bib9], [@bib8]). Large-scale growth performance studies with grower-finisher pigs, however, are still lacking. In the current study, it was clearly shown that, compared to the non-supplemented control, both 0.3% and 0.5% benzoic acid can improve the ADG by 6%, ADFI by 3%, and FCR by 3% for the whole grower-finisher duration. The derived optimal supplemental level of 0.36% of benzoic acid for grower-finisher pigs in the current study indicates that grower-finisher pigs might need less benzoic acid than nursery pigs for the best growth performance. Furthermore, there was no sign of health problems with the grower-finisher pigs linked to the long time usage of benzoic acid at the supplemental levels in the current study, which is probably due to the efficient extraction of benzoic acid by the liver and clearance by the kidney ([@bib7]).

5. Conclusion {#sec5}
=============

In conclusion, the dietary inclusion of benzoic acid at the supplementation levels of 0.3% and 0.5% significantly improved the growth performance of both nursery and grower-finisher pigs in the current study; the nursery pigs responded to the supplementation level of benzoic acid up to 0.5% linearly while the grower-finisher pigs achieved the optimal ADG at the calculated supplementation level of 0.36%.

Peer review under responsibility of Chinese Association of Animal Science and Veterinary Medicine.

[^1]: Treatment premix is made of silicon dioxide replaced with intended levels of benzoic acid.

[^2]: Supplied per kilogram of diet: vitamin A, 9,750 IU; vitamin D~3~, 3,000 IU; vitamin E, 63 mg; vitamin K~3~, 3.0 mg; vitamin B~1~, 3.0 mg; vitamin B~2~, 9.6 mg; vitamin B~6~, 4.5 mg; vitamin B~12~, 36 μg; D-biotin, 240 μg; D-calcium pantothenate, 30 mg; folic acid, 1.8 mg; niacin, 36 mg; Cu (tribasic copper chloride), 190 mg; I (potassium iodate), 0.6 mg; Fe (ferrous sulfate), 120 mg; Mn (manganese sulfate), 60 mg; Zn (zinc sulfate), 120 mg; Se (sodium selenite), 450 μg; and choline (choline chloride), 300 mg.

[^3]: Supplied per kilogram of diet: vitamin A, 6,500 IU; vitamin D~3~, 2,000 IU; vitamin E, 42 mg; vitamin K~3~, 2.0 mg; vitamin B~1~, 2.0; vitamin B~2~, 6.4 mg; vitamin B~6~, 3.0 mg; vitamin B~12~, 24 μg; D-biotin, 160 μg; D-calcium pantothenate, 20 mg; folic acid, 1.2 mg; niacin, 24 mg; Cu (tribasic copper chloride), 125 mg; I (potassium iodate), 0.5 mg; Fe (ferrous sulfate), 100 mg; Mn (manganese sulfate), 50 mg; Zn (zinc sulfate), 100 mg; Se (sodium selenite), 250 μg; and choline (choline chloride), 250 mg.

[^4]: Supplied per kilogram of diet: vitamin A, 6,500 IU; vitamin D~3~, 2,000 IU; vitamin E, 42 mg; vitamin K~3~, 2.0 mg; vitamin B~1~, 2.0; vitamin B~2~, 6.4 mg; vitamin B~6~, 3.0 mg; vitamin B~12~, 24 μg; D-biotin, 160 μg; D-calcium pantothenate, 20 mg; folic acid, 1.2 mg; niacin, 24 mg; Cu (tribasic copper chloride), 30 mg; I (potassium iodate), 0.45 mg; Fe (ferrous sulfate), 80 mg; Mn (manganese sulfate), 40 mg; Zn (zinc sulfate), 80 mg; Se (sodium selenite), 150 μg; and choline (choline chloride), 250 mg.

[^5]: The first and second batches of diets for grower phase of experiment 2.

[^6]: The first and second batches of diets for finisher phase of experiment 2.

[^7]: SEM = standard error of the means; ADG = average daily gain; ADFI = average daily feed intake; FCR = feed conversion ratio, ADFI/ADG.

[^8]: Linear effect of benzoic acid.

[^9]: Quadratic effect of benzoic acid.

[^10]: SEM = standard error of the means; ADG = average daily gain; ADFI = average daily feed intake; FCR = feed conversion ratio, ADFI/ADG.

[^11]: Linear effect of benzoic acid.

[^12]: Quadratic effect of benzoic acid.